Named so as the pattern of ISZ resembles an unlit Beacon. The first 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):
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
