Named so as the pattern of ISZ resembles an unlit Beacon. This opening template existed beforehand in the Japanese Community as スピアード積み(Speerde Stacking).
After Kaidan this opener aims for stable 6-3.
General Shape
To rotate the I into position J, LO, or JOL tetrominos must be placed if not performing a wallkick. In games with symmetrical I rotations this cannot be done with J alone.
The First Bag has a 20.00% Perfect Clear chance, 3 solutions.
Main Stacking Method
This can be assembled 85.56% of all bags with one soft-drop, or 90.87% for two or more.
With mirror these values become 92.38% and 95.24% respectively.
Heart Variation
By alternating the heart shapes this covers 78.89% of all bags, resulting in favourable residue to freestyle 6-3.
Common ideas are to keep L or O in hold to fix height difference after a floating T-spin.
Other frequent stacks include the folllowing, the latter of which results in a 51.75% Perfect Clear chance with other Perfect Clear continuations that lead to a potential loop.
These Mechanical TSD setups are also possible with potential for Perfect Clears (see link):
Mismatched Heart
It is also possible to stack like so 50.00% of the time if the LS heart shape comes in the wrong order. While a mismatched OJ is possible the residue is undesirable.
All Cover Variation
Covers 100% of bags, can be used independantly or when the Heart variation fails.
- L>O: Look for which of L or S come first. If possible place S/Z as in diagram two after taking a T-spin, otherwise place Z rightmost always.
- O>L: For the sequence SJO use the last diagram, provided by metallicLurker, when unable to hold. The second template will suffice for 180 rotations.
Triple Double Upgrade
Upgrading into a TD Attack is possible but reduces stacking options.
Perfect Clear
Stacking for a Tetris works for both T placements. It also provides a Perfect Clear chance after 8 Lines meaning one can use DPC Setups afterwards to return to a fresh bag.
See Also
Interchangeable Shapes