Hachispin

Hachispin (or Hachi-Cannon) is an opener created by a Japanese player with the same name. The setup consists of a T-Spin Single followed by a T-Spin Triple and Perfect clear.

First 2 bags
The setup needs an early O piece. A T-Spin Single is made at the end of the first bag and a T-Spin Triple at the end of the second bag.

Under circumstances, the second S piece needs to be soft-dropped. The second L, I and O pieces can be dropped in different ways. If possible, drop the second I piece 2 columns away from the wall because this gives a chance for a Perfect clear.

Perfect Clear continuation
If the second I piece is dropped 2 columns away from the wall, then there's a high chance (69%) to make a Perfect clear (PC) at the end of the third bag (4 further cleared lines) whereas either the third I, L or J piece will stay on hold. The chance is especially high, if T piece comes first in third bag (94%), and also decent if either S, Z or O piece comes first (between 70% and 73%). The PC will always work, if Z and T can be used to fill the bottom rows (see picture 1). Same is true for T and L (see picture 2). Picture 1 shows the most common way to make a PC.

If the second I piece is dropped adjacent to the wall with the L piece above, then there's still a small chance (19%) to make a PC. Again, the chance is the highest if T comes first in third bag (40%). However, all PC opportunities are hard to spot. It is required to clear the third line before placing the Z piece adjacent to the left wall.

If the second I piece is dropped adjacent to the wall but the second L piece is kept on hold until the T-Spin Triple is made, then the chance to make a PC is increased to 74%. Note that this number is a little theoretical though because one can't see or think that many pieces in advance. The 11 most frequent PC opportunities are shown below. Note that the first 3 pictures are similar to the builds where you drop the I piece 2 columns away from the wall (same is true for the pictures in the bottom row). Also interestingly, all these 11 ways can be pulled off more often than the 4 ways shown above where you dropped the L piece horizontally adjacent to the right wall.

T-Spin continuations
There are also easy ways to make either a T-Spin Double or T-Spin Triple in the third bag. Sometimes, it is also possible to prepare an Imperial Cross.

Examples
code=m115@2gQ4IeR4DewhDeQ4ilAewhBtAeRpgli0whAeBtRpCe?g0whJeAgHvhBFlBAAAAhwhIexhDeQ4AeSpwhi0AeQ4AeBtx?wCeglQ4JeAAArgwhEehlRpwhBtDeglRpwhAeBtR4Aeglh0w?hBeR4Ceg0Ieg0SeAAAvhBdoBAAA9gRpBti0ilRpQ4Btwwg0?glh0xwQ4BtxwR4g0glDewwR4LeAAAvhAAAA code=m115@vhUyQYvAFLDmClcJSAVDEHBEooRBMoAVBz3/wCJHWW?CvnNPCzfLuCP+VWCT+lFDvifBAXtBspBumBZkBzlB9nQpAF?LDmClcJSAVztSAVG88AYe88A5mbMCKNUPCa9CMC0yLMC0HL?WCqAAAAToB0gBxiBOaB3cBtkBmfBEqBqlBThBvnBpoBatBX?He 

pwn_by_numbers variation
If you get an early L or J piece but no early O piece, then you can still try this variation. It's probably best to place the T piece vertically instead of upside down. With some luck you can fill the right corner with an S piece and make a T-Spin Triple at the end of second bag.

Note that in this variation, it's harder to follow up with a T-Spin Double (T-Spin Triple is still easy). However, if you can stack the second bag like shown above, then there's a very high chance (83%) to make a Perfect clear (PC) at the end of third bag. The chance is especially high (95%), if S piece comes first in second bag. The chances are also very high (between 88% and 89%), if you receive L or J piece first. The PC will always work, if Z and L can be used to fill the bottom rows (see picture 2). The PC will also always work, if the third bag starts with Z and J piece, although the player must be flexible where to put the J piece (either at left wall or at the bottom). The first 2 pictures show the most common ways to make a PC.

Another way to make a T-Spin Triple at the end of the second bag is shown below. The right corner is left empty, then covered by an O piece and eventually uncovered by the T-Spin Triple line clear. L piece must stay on hold through second bag.

If you can stack the second bag like shown above (note that the second L piece hasn't been dropped yet), then there's a 96% to make a Perfect clear. Note that this number is very theoretical though because one can't see or think that many pieces in advance. The 11 most frequent PC opportunities are shown below; there are just too many ways to show them all.