Opener

The following article lists ways how to start a game on Tetris Guideline rules:


 * Bag Randomizer: every shape (I,T,O,L,J,S,Z) appears exactly once every 7 pieces
 * Hold feature: the player can store away pieces for later use (e.g. hold a T piece to make a T-Spin later on)
 * SRS kicks: if a rotation fails without offset, then the game tests a few other nearby locations; kicks are required to make T-Spin Triples
 * multiple Previews: you can see which pieces will appear next
 * T-Spins: twisting a T piece into a tight space is rewarded
 * Combos: clearing lines with consecutive pieces is rewarded
 * Perfect Clear: reaching a completely empty playfield is rewarded

It is implied that the reader is aware of what placements can be done in the Super Rotation System (e.g. see SRS). This article majorly focuses on multiplayer and versus matches. Combos and Perfect Clears don't score many points in singleplayer and for scoring purposes it's usually best to use a looping T-Spin technique like Infinite TST or ZT Stacking. Here's what a line clear sends depending on the client:

b2b stands for Back-to-Back. A Tetris or T-Spin line clear collects the back-to-back bonus, if the last line clear was also either a Tetris or T-Spin (and not a regular Single, Double or Triple). Here's what a combo sends (additional to the line clear):

And finally what a Perfect Clear sends. Note that in most games, the game will scrap the lines sent by combos and line clears when a Perfect Clear occurs.

The consistency of garbage also influences of how important Openers are. All games will use exactly one hole per garbage line but the position of this hole may be influenced by certain factors (resulting in a hole change rate). The garbage in Tetris Friends and Tetris Online Japan / Poland is pretty clean, so garbage can be cleared pretty quickly. In those games, T-Spin Openers will have barely any effect, except if the opponent uses Combos or Perfect Clears. However, in Puyo Puyo Tetris the garbage column may change during an attack, so even garbage from Tetris, T-Spins and Perfect Clears can become messy by chance. An attack usually means all garbage sent by one line clear (including combo and back to back bonus, also note that multiple line clears can become one attack in Puyo Puyo Tetris when stalling a little). However, in Tetris Battle, lines sent through combos and back-to-back are treated as separate attacks, resulting in more messy garbage there. Note that the numbers for Tetris Battle stand for the Arena mode; bombs will always switch columns after each row. Garbage Blocking means delaying the insertion of garbage until a combo breaks.

= T-Spin Openers =

T-Spin Openers focus on making a few T-Spin line clears within the first 3 bags or so. A T-Spin is a placement of a T piece where the last move was a rotation and where at least 3 of the 4 corners are filled. The T's middle finger points towards 2 of those corners; if only 1 of those 2 corners is filled, then the T-Spin is just counted as a T-Spin Mini - unless the last rotation kicked the T-piece 2 rows down and 1 column to the side ("T-Spin Triple kick").

The Openers in this section are arranged by which pieces are required to come early in first bag. One could also arrange the techniques by when the first T-Spin is made (single bag opener vs cannons).

early I piece
Placing the I piece flat in the middle is the most common way to start a game with an I piece. There are several ways to continue this placement with a T-Spin Double within a single bag (first 7 pieces), usually by placing the S or Z piece horizontally on top of it and the O piece in the opposite corner. Those ways result in a flat stack and allow to make a second T-Spin Double within another bag. Those ways have become known as TKI openings in the English speaking community, although the TKI 3 Opening just represents a special way in the Japanese community (which uses TKI to refer to Triple Double attacks).

TKI 3 (Fonzie variation)
This way involves placing the J piece flat on top of the O piece. It results in 2 T-Spin Doubles within the first 2 bags followed by a Perfect Clear opportunity after 6 cleared lines.



Here are all basic ways to get a Perfect Clear after the second T-Spin Double. All of them require to get an O or I piece within the first 2 pieces of the third bag.



There are some further possibilities when substituting the T-Spin Double with a T-Spin Single. Here a J piece is required to come early in the third bag.



TKI 3 (Flat Top variation)
This way involves placing the J piece upside down on top of the Z piece (there's another way as shown in the first picture). It results in 2 T-Spin Doubles within the first 2 bags followed by a very likely third T-Spin Double within another bag when placing the second bag's L, J, O and I pieces on the right side.



If the Z piece appears early in second bag, then you can get some further T-Spin Doubles by using the following technique resembling ST Stacking.



LST Stacking as shown in this video is also an option.

TKI 3 (Castle Top variation)
This way involves placing the J piece vertically on top of the O piece. It results in 2 T-Spin Doubles within the first 2 bags followed by a third T-Spin Double within another bag when placing the second bag's L, J, O and I pieces on the left side.



There are several ways how to stack the T-Slot in the third bag. However, the way shown in picture 5 below is usually the best because it allows to make a T-Spin Triple within the fourth bag. This way is also known as the TKI 3 Opening.



Another way to continue the TKI Castle Top variation is by building an Imperial Cross in the second bag. This is usually possible with an early Z piece.



Imperial Cross is a technique that usually results in two T-Spin Doubles. If the overhang was stacked with a S piece, then there's also a good chance to get a Perfect Clear. In this case, the second T-Spin will be usually downgraded to a T-Spin Single.



early L or J piece
When starting with a L or J piece, there are several ways to combine it with the first bag's S and Z pieces to prepare a T-Spin. Some of these ways even result in a small PC chance after 4 cleared lines (e.g. MKO Stacking). However, the most popular technique is DT Cannon.

DT Cannon (LS / JZ base)
DT Cannon is a technique that results in a T-Spin Double followed by a T-Spin Triple within the first 3 bags. Thereby, the first T piece is wasted in the stack and the first T-Spin is usually delayed as much as possible. The most common way to stack a DT Cannon are the LS and JZ bases which both result in the same stack (pictures 1 & 2). While the LS base can be executed very quickly (no rotation needed for LJSZ; pieces either can be hard-dropped immediately or are placed on the walls), the JZ base can always be used when starting with a J piece (the Z piece can still be spun into its place even after T and O are placed). There are several ways to stack the second bag, e.g. preparing a side-stacked 4 wide, a C-Spin or a second DT Cannon (like shown in this video). However, the most common way results in a flat stack after 3 bags and a Perfect Clear opportunity after 10 cleared lines.



Here are all basic ways to achieve the Perfect Clear. There are more possibilities, if the third O piece was placed in the top-right corner.



If the Perfect Clear is not executable, then one can often fall back on this Donation T-Spin Double.



MKO Stacking
MKO Stacking is a technique that usually results in a Perfect Clear after 4 cleared lines or 2 T-Spin Doubles within the first two bags. Unfortunately, both L and J are required to come early in first bag and the first T-Spin cannot be entirely prepared within the first bag. So, if T the piece comes first in second bag, the player is stuck with 2 T pieces and must use one to make the T-Spin overhang (provided the PC doesn't work which is always the case of a late second O). Otherwise, the T-Spin overhang can be made with the S or Z pieces. There's a decent but hard-to-spot Perfect Clear opportunity after 8 cleared lines, if the pieces are stacked like shown in the fifth picture.



Here are all ways to get a Perfect Clear after 4 cleared lines. 2 O pieces and an even number of T pieces are required.



If the T piece comes early in second bag but no Perfect Clear is possible, then the player can try something like Cut Copy.



Pokemino's STD
Pokemino's STD is a technique that results in a T-Spin Single within the first bag. It's usually followed by a T-Spin Triple into T-Spin Double within the next 2 bags. It's almost always stackable because the only stacking dependency in the first bag is J piece before Z piece. However, it's one of the weakest techniques on this page, majorly because the T-Spin Triple cannot be entirely prepared within the second bag and the T-Spin Triple overhang requires placing another piece after the I piece. So, the player will be in trouble, if either T or J come first in second bag.



As mentioned before, the T-Spin Triple cannot be entirely prepared within the second bag. So, if T the piece comes first in third bag, the player must decide between using one T piece in the stack to prepare the T-Spin Triple or splitting the T-Spin Triple into a T-Spin Double followed by a T-Spin Single as shown below.



early O piece
One could assume that it's troublesome to make a T-Spin when starting with an O piece. However, there are decent setups that even work when the O piece is immediately followed by S, Z or T. You can often prepare a T Spin by putting S on top of the O piece and Z next to it (or with the roles of S and Z swapped) whereas one of them will be placed vertically and the other horizontally. Hachispin (piece on top is placed vertically) and Albatross (piece on top is placed horizontally) work this way.

Mr. T-Spin's STD (reversed)
Mr. T-Spin's STD is like Pokemino's STD a technique that always allows to make a T-Spin Single followed by a T-Spin Triple and a T-Spin Double within 3 bags. It will always work when starting with an O piece and if Z piece shows up before L piece. The O piece just works as a base for an I piece placement, the T-Spin Single is achieved with a ZLJ combination. The rather weird placements of S and I will be used later to build a Triple Double Attack (reversed C-Spin). Note that the stack in the right 4 columns doesn't interact with the stack in the left 6 columns. So, this setup can also be built with the left part and right part swapped (not mirrored) which is indeed the real Mr. T-Spin's STD.



In the second bag the S, Z and O pieces always form this "Plus" shape which can be done in 4 different ways. The J piece is placed vertically on top of the first bag's I piece forming the Triple Double Attack overhang. The second bag is finished with a T-Spin Triple.



There are many different ways to achieve the T-Spin Double in the third bag. If possible leave the I piece on hold. After the T-Spin Double is done, the I piece can be placed in 9th column to get a Tetris in the fourth bag.



If L piece shows up early in the third bag, then it can be used to create the Triple Double Attack overhang instead of the J piece from the second bag. The weird J piece overhang is pretty much the only downside of this technique.



Hachispin
Hachispin is a technique that always allows to make a T-Spin Single followed by a T-Spin Triple within the first two bags. Hachispin is always executable when starting with an O piece and receiving J piece before L piece. In second bag L, S and Z are always stacked as shown below. The stack on the left side (J,O and I pieces) will vary.



Hachispin can always be continued with a T-Spin in third bag. A T-Spin Double can be prepared with nothing but a L piece. Some more advanced T-Spin techniques like T-Spin Triple, Imperial Cross and Single Double (SD1) are also possible.



If in the second bag J, O and I pieces are placed like shown in the following 5th picture, then there's also a chance to get a Perfect Clear after 4 further lines (8 cleared lines in total).



Albatross
Albatross Special or short Albatross is a single bag opener that results in a platform T-Spin Double. It is usually followed by a T-Spin Triple which can be often achieved at the end of the second bag. Albatross is always executable when starting with an O piece and receiving L piece before J piece, so Albatross has almost the same piece dependencies as the mirrored version of Hachispin. However, it can still be useful to learn both techniques: When starting with an O piece and placing it 3 steps away from the (left) wall, then either Hachispin or Albatross will always be executable. To build the T-Spin Triple with just pieces from the second bag the O, S, Z and I pieces must be placed like shown in the 5th picture. Note that with a proper spin the S piece can even be placed after O and Z.



There's a nice continuation, if the T-Spin Triple is finished in the second bag. In this case pieces can always be placed like shown in pictures 2 and 3 which results in a T-Spin Double. On top of it, there's a chanced to get a Perfect Clear in 3 further lines (10 cleared lines in total).



Number One
Number One is a single bag opener that results in a platform T-Spin Double. Thereby, the first T piece is spun into a vertical position like in STSD which makes it different from most other platform openers. It has quite some dependencies in the first bag (L after O, Z after S, J after I) but despite of its look it's a really good opener if applicable. The first bag is placed like this:



There's a single floating mino in row 2 located on the right side. However, with SRS spins it's possible to fill the area beneath it, and prepare a T-Spin Double into horizontal position as if the setup was just a regular STSD. Note that in picture 3 J piece must be spun 2 times to reach the desired location.



However, the really nice thing about the Number One setup is that there are two different continuations that result in 2 further T-Spins (first one is a T-Spin Double) with a chance for a Perfect Clear after 8 cleared lines in total.

The first continuation looks like a T-Spin Triple setup but with an empty cell in row 2. So it just results in a T-Spin Double and the empty cell can be used to prepare another T-Spin. This continuation can be reached by spinning the J piece beneath the floating mino whereas there are 2 different paths; one where J is placed horizontally (picture 3) and one where J is placed vertically (picture 2).



The resulting fields look a bit different for each path. Here are the ways that can result in a third T-Spin (sometimes even T-Spin Double) and a Perfect Clear at the same time.



The second continuation involves building an Imperial Cross with the remains of the STSD. There are 2 different paths again; one involving a L-Spin (picture 3) and the other involving a Z-Spin (picture 2).



This time the PC chances are smaller compared to the first continuation. In one path there isn't even any way to reach both T-Spin Double and PC at the same time. On the bright side, the T-slot is already built at the end of the second bag.



early S, Z or T piece
Starting with a S, Z or T piece is basically the worst thing that could happen, if you want to go for a T-Spin Opener. If you start with a T piece, then you have to waste it in the stack or keep it on hold for a rather long time. If you start with S or Z, then you have to use softdrop, make a platform T-Spin or just make a T-Spin Single. However, there are a bunch of techniques that address those bags. For example for a STO or SZO start, you can always use Mr. T-Spin's STD. Or for an STL or SZL start, you can always use Pokemino's STD. Or for an STI or SZI start you can use one of those TKI 3 setups on condition that you softdrop the I piece. However, for a SZT start, you are pretty much forced to use one of the following techniques.

Pelican
Pelican is like Albatross a single bag opener that results in a platform T-Spin Double and is usually followed by a T-Spin Triple. In case of a S piece start it's always executable, if J piece shows up before L and O. In order to finish the T-Spin Triple in the second bag, the O, I, S and L pieces must be placed like shown in the 5th picture.



There's a nice continuation, if the T-Spin Triple is finished in the second bag. In this case the third bag's pieces can be be placed in a way that results in a T-Spin Double followed by a chance for a Perfect Clear after 3 further lines (after 10 cleared lines in total).



DT Cannon (TSZ base)
DT Cannon is a technique that results in a T-Spin Double in the second bag and a T-Spin Triple in the third bag. People usually use the LS / JZ base variant of the DT Cannon. However, there's also a DT Cannon applicable for TSZ starts. It needs more keystrokes in first bag and it doesn't have as nice continuations. On the other hand, the stack will look pretty solid after 2 placed bags (picture 2) and under circumstances the stack can become flat after 3 placed bags (like shown in the 5th picture).



Here's another way to stack the second bag (picture 2) and the third bag resulting in the same flat stack. In the second bag one could also choose a different position for the I piece (e.g. on top of the S piece).



The shown flat stack has some Perfect Clear possibilities which may work up to 79 % of the times (not all possibilities are listed). However, it's hard to perform a further T-Spin without losing the back-to-back bonus.



BT Cannon
BT Cannon is like DT Cannon a setup that results in a T-Spin Double followed by a T-Spin Triple within 3 bags. It can be used on a wide range of first bags, among others for a T piece start paired with early S and Z pieces.



The overhang can be built in 2 different ways in the second bag. In the third picture, J piece and S piece can be spun into position even after Z and L are placed. The second T piece is used to make a T-Spin Double. The stack should always look the same after 2 placed bags.



The BT Cannon can be followed by a reversed C-Spin (Triple Double Attack). This one can be troublesome, if T piece comes rather late because the C-Spin can block the entrance to the remaining parts of the BT Cannon (T-Spin Triple).



The fourth bag is majorly placed on the left side. There are multiple ways to do so. Only 2 different stacks are shown. The C-Spin overhang is also finished followed by yet another T-Spin Triple.



There's a good Perfect Clear opportunity after five bags. The stack shown in pictures 4 and 5 above has these 3 different solutions below which will additionally clear a T-Spin Double (which is still left from the C-Spin). The stack shown in pictures 1 and 2 above has 2 similar solutions. If the T piece comes rather late, then Trinity / STSD is also an option (picture 2 below).



C-Spin
C-Spin is a kind of Triple Double Attack. As the name suggests, it results in a T-Spin Triple which is usually followed by a T-Spin Double within three bags. As an opener it's most often built with a SZT core whereas L and J are used to build the overhang. O and I piece are placed on the right side, sometimes along J piece (the second bag's J piece can also be used to build the overhang). The 6th picture shows a possible follow up, namely a STSD after the T-Spin Double (or Trinity respectively).



The first bag can be placed like this:



The second bag can often be placed in a way that before placing the last piece the right side is perfectly flat with a 3-columns wide gap to the overhang:



As said before, one piece from the second bag is not placed in those pictures above. It can be a S, Z, I or O piece. We assume that the T-Spin Triple is made before placing that piece. The player can also try to replace the following T-Spin Double with an Imperial Cross or T-Spin Triple depending on the remaining piece. In case of a T-Spin Triple, the new overhang can also be used to build another C-Spin (not shown).



Similar things are also possible in case of a 2-columns wide gap.



Unnamed SZ Techniques
Those techniques results in a T-Spin Single after placing S and Z pieces horizontally one column away from each other and completing the second line with L, J, I and O pieces somehow. Those techniques are pretty much meant as last resort only. The T-Spin overhang can be stacked in many different ways, so can the right side. In last picture the I piece is soft-dropped and kicked into its final place.



While the build in the last picture should be followed by a Tetris, all other builds can be followed with a T-Spin Double (or maybe T-Spin Triple). Imperial Cross is also a decent continuation for the first build because of the chance to get a Perfect Clear.



Fourth Picture can result in those Perfect Clears (among many others):



Fifth picture can result in this Perfect Clear:



Subscriber Special is yet another way to stack the overhang and complete the right side. It can be followed by a STSD. L piece must be placed after completing the second line. The second T-Spin Double can also be converted into a T-Spin Triple or an Imperial Cross.



= Combo Openers =

A Combo is the act of clearing lines with consecutive pieces. Thereby the game counts how many pieces in a row are clearing at least one line (without any interruption). Two consecutive clears result in a 1 combo, three consecutive clears result in a 2 combo, and so on. In multiplayer, clients send lines each time the combo counter is increased beyond a certain threshold (which is usually 2). The higher the combo counter, the more lines are sent. A Single line clear can send 4 or even 5 lines, if the combo counter is high enough.

The easiest way to make a big combo is building a huge rectangular tower on one side while leaving a certain amount of columns empty. Common strategies are 2 wide, 3 wide and 4 wide where the number denotes the amount of empty columns. Building a huge tower is a risky but also rewarding strategy: The combo player may be topped out by a well-timed spike, he or she may need some time to reach any received garbage lines, misdrops can become deadly mistakes and the combo may be interrupted in the middle (resulting in fewer sent lines). On the other hand, if the opponent can't send lines fast enough to keep the tower short, then he/she will receive a lot of lines in quick succession and may be topped out in return. Under circumstances, the combo player can also use incoming garbage lines to extend the combo.



You can see examples for 2 wide, 3 wide and 4 wide above whereas 3 bags have been placed in each. You can easily see the advantage of 4 wide over 2 wide: In average, the 2 wide stack will shrink by 2 lines for each dropped piece while the 4 wide stack will shrink by only 1 line. This means, 4 wide can potentially reach a higher combo. While clearing multiple lines at once will also send some lines, this bonus is not nearly as big as for reaching big combos. Moreover, the 4 wide tower is a little higher although the same amount of pieces have been used to create those towers. This means 4 wide can be build a little faster.

On the other hand, 4 wide is also harder to maintain. You have less options to place a piece on a 6 wide tower than on an 8 wide tower. Keeping the combo going is harder on 4 wide: while you have to place each piece just vertically in a 2 wide, pieces must clear exactly 1 line (with a few exceptions) to keep the combo going in a 4 wide. While you can leave the leftmost columns empty in a 2 or 3 wide, you should pay attention to the number of filled cells in those columns in a 4 wide.

Note that you can also combine those setups: A few rows of 2 wide at bottom (where you can place S, Z and T pieces), a few rows of 3 wide (where you can place L and J pieces) and a few rows of 4 wide on top (where you can place I pieces). However, such stacking is not necessary with Hold feature and you won't reach the full potential of a proper 4 wide.

We will not discuss 2 wide and 3 wide in the next sections. 2 wide is very ineffective compared to 4 wide. 3 wide performs a little worse than 4 wide but you can do it without softdrop.

Side 4 Wide
In the picture above, you could already see an example of side(-stacked) 4 wide: A big 6 wide tower on the left side, the right 4 columns are almost empty, just 3 filled cells in the bottom rows. Latter is also known as residuals; the amount of residuals will not change as long as a single line is cleared with each piece. 3 residuals is most common. The Combo Setups article will tell you how the 4 columns can look like during a successful 4 wide and which placements can be done to maintain the combo.

The 3 filled cells (residuals) are created by placing a piece partly overlapping with those 4 columns:



Center 4 Wide
The comboing (successively clearing lines) in center 4 wide works exactly the same way as in side(-stacked) 4 wide. The only difference is how the tower is built. Instead of a huge 6 wide tower on one side, we will have two 3 wide huge towers on each side which means that the 4 columns in the center of the playfield stay almost empty (again 3 filled cells).

The advantage of this technique is that it circumvents the top out mechanics. There are 2 ways to top out in guideline games: a) you place a piece entirely over the visible area, b) a piece spawns colliding with one filled cell of the stack. This means the player is only topped out, if the bottom of the center 4 wide is pushed to the very top by garbage.

So it's a more defensive strategy. It's more effective against T-Spin and Perfect Clear openers. However, it has a disadvantage, too: It's harder to stack the towers and it may prove difficult to build the towers almost equally big.

Here are the basic ways to place the first bag. The first setup will usually work when receiving S piece or Z piece before T piece. The second or third setup will usually work when receiving T piece before S piece and Z piece. Only bags with early O but late L and J will prove difficult. Here, the fourth setup may work best.



After the first bag the surface of the towers will usually look like this: one tower is perfectly flat and the other looks like it had a T piece (flat side down) on top. The second bag can usually be placed in one of the following ways preserving the perfectly flat structure of that one tower and letting the other tower always look the same way (besides mirroring). Note that in any of those cases the L and J piece are dropped on the flat stack, supplemented with either O, S or Z. T piece and I piece belong on the other tower.



More issues can occur during the third bag. If possible, place the pieces like in pictures 1 to 4 which result in the same stack (besides mirroring). But you may be forced to do things like in pictures 5 or 6 (or even worse) where you will need another O and / or I piece to flatten out the formally flat side.



A further way to place bags 2 and 3 is shown below. It also results in the stack known from pictures 1 to 4 above. The left tower is not flat after the second bag but the small cliff is compensated in bag 3. Note that in the second picture you can place S piece before L and J (softdrop required).



The longer the game goes on, the harder it's to predict what will happen. Under some circumstances you can combine an O piece and two L pieces to a rectangle. Or it's better to leave out 4 cells located above each other which will be filled later with an I piece (via softdrop). Or leaving out 4 cells in the shape of a T.

6 Residuals
So far we have only considered 3 filled cells in the 4 almost empty columns. 6 filled cells is also an option. While it will not be used in side 4 wide, it's not that uncommon in center wide. Here are some basic ways to place the first bag in center 4 wide with 6 residuals.



Pictures 4 to 6 belong to picture 3: There will only be 2 filled cells in the center columns after the first bag and it will stay like that until the player must get rid of a piece or start the combo.

Comboing is pretty similar to 3 residuals. Usually, there's only one empty cell in the bottom row (often located in the center 2 columns) which means there are 3 filled cells above this line. So, 6 residuals is equivalent to receiving an extra garbage line with a hole in said column.

= Perfect Clear Openers =

A Perfect Clear (PC) means having no filled cells left after a line clear. The Tetris guideline rewards such an occurrence. Usually, a PC sends 10 lines in multiplayer (whereas most games won't send additional lines from combos, T-Spins and clearing multiple lines at once). Perfect Clears can only be achieved after a minimum of 4 cleared lines at the start and they can only appear after an even amount of cleared lines, if no garbage is received.

The Standard PC Opener
There's one basic setup that is used to start the game with a Perfect Clear:

Note that getting a Perfect Clear is not guaranteed with this setup. The chances just lie around 61.2 % (the chances can be increased a little by leaving the first I piece on hold). 3 of the first 4 pieces of the second bag are used to complete the 4 lines in one of the following ways:

a Second Perfect Clear
Note that one Perfect Clear doesn't send much more lines than 2 T-Spin Doubles and there's a chance that the PC fails (e.g. if the opponent sends lines early). However, if the first PC is successful, then there's a decent chance to get a further Perfect Clear in which case the PC Opener will send more lines than any other setup in the same amount of time (3 bags or less).

Note that we have already placed 3 pieces of the second bag to achieve the first PC. How the second Perfect Clear is attempted depends on the 4 remaining pieces of the second bag. If those pieces include an O piece but not more than one of T, S, Z, then there's a chance to get a second PC after 2 further cleared lines (chance also depends on the first pieces of the third bag).

If this setup doesn't work, then there's still a chance to get a Perfect Clear after 4 further cleared lines (8 cleared lines in total). More precisely, if done properly the success rate will even be bigger than for the first PC and in some cases the second PC is even guaranteed. In the following we will make a case differentiation of how the 4 remaining pieces of the second bag look like, namely if they include T, L and J piece.

either L or J
This is the most likely case: From T, L and J, only either L or J are left.

If the other 3 remaining pieces are S, Z and O, then they can be stacked like this:



Now the third bag has to be placed, more precisely 6 pieces of the third bag whereas the 7th piece will stay on hold. And that's the nice thing for the second PC: you can predict which pieces are given to the player at the end of the PC, so you can plan ahead accordingly and predefined "solutions" exist.

This setup has a 80 % success rate which even becomes 100 %, if the T piece is among the first two pieces of the third bag. 80 % success rate means that 80 % of the 5040 possible bags (piece combinations, sequences) can be stacked in at least one of the following 5 ways (with the use of hold):



If there's no way to get a Perfect Clear, then the player can try T-Spin techniques like STMB Cave.

LSZO and JSZO can also be stacked in the following way which even gives a higher chance for PC but in return makes the PC possibilities harder to spot. Additionally, JSIO and LZIO can be placed in a way that results in the same stack which is usually also true for LSZI and JSZI:



The corresponding success rate is 91.0 %.



There are other ways how the 4 remaining pieces can look like in case of "either L or J". However, these combinations shouldn't occur after a successful Standard PC Opener.

neither L nor J
From T, L and J, no one is included in the 4 remaining pieces of the second bag. That means we have the combination SZIO which can be placed in this way:



The corresponding success rate is 94.0 % and it even becomes 100%, if the T piece is a among the first two pieces of the third bag. The third bag should be placed like this:



Note that this build also works for a sequence involving both L and J (more precisely LJZI and LJSI).

both L and J
From T, L and J, only L and J are included in the 4 remaining pieces of the second bag.

Basically, all possible combinations except LJSZ can be placed like this:



The success rate is 95 % which even becomes 100 %, if the T piece is among the first two pieces of the third bag. The last 3 shown solutions are not really needed.



In case of the piece combinations LJSZ and LJSI / LJZI (maye needed for later I) the player may still stack the rest of the second bag like this:



This setup has a 93.3 % success rate which even becomes 100 %, if either I piece or O piece is among the first two pieces of the third bag. The setup has a bunch more solutions but they are only needed, if you want to have another piece on hold at the end of the third bag.



There are setups that have a 100 % success rate for all those piece combinations but the solutions are also harder to spot, e.g. see Perfect Clear Opener article. Generally setups for both L and J will have a lot of different solutions and if a T piece is used in third bag, then at least one piece must be split in 2 parts in the illustrating pictures (one of those parts being a single mino separated by an odd number of lines by the other 3 minos).

T piece
Let's consider the last case, namely that the T piece is among the 4 remaining pieces of the second bag. In this case, either L or J will be among those pieces as well (but not both at the same time). This is the nicest of all cases with success rates at 100 % or close to it. The most frequent solutions will also be relatively easy to spot (with no piece split in 2 parts in the illustrations).

If the piece combination can be stacked like this, then do so:



The success rate is 100 % by only using one of the first 3 solutions. This means every bag can be be stacked like shown in one of the first 3 pictures (in fact the pairs 1 & 3 and 2 & 3 already cover all bags).



If S and Z are both left among the 4 remaining pieces, you can stack this tub:



This has the advantage that the stack is pretty symmetric and the solutions have a nice structure. However, the success rate just lies at 99.8 %.



If the piece combination contains both O piece and I piece, then you can stack flat like this:



The success rate is 100 %.



Another pretty solid choice which covers a big variety of piece combinations is the following. It's not really needed when using the other 3 stacking styles.



The success rate is 100 %, although some bags may force the player to use I-Spins.