Hardtack Stacking

Hardtack Stacking (Japanese name... 乾パン積み) is one of the TD Attack openers. it always does TST in the second bag and can do TST or TSD in the third bag. 8-lines T-Spin PC does not exist, so you cannot fight with PC as the main axis. But instead, it is very good that the first bag can be setup without softdrops from pesky TZSO and TSZO, the second bag has no softdrops at all except T-pieces, and the derivation is excellent. This opener was invented by Sioyaki.

1st bag
The setup rate is 54.44% if softdrop is allowed and 23.33% if not allowed(with left-right reversal).

The foundation pieces are O-piece + Z-piece or S-piece when softdrop is allowed, and O-piece + Z-piece + S-piece when not allowed.

All subsequent descriptions are right roof.

2nd bag

 * J>L


 * L>J

If the J piece is faster than the L piece, use the top, if the opposite, use the bottom. In either route, the O, Z, and S pieces are interchangeable in placement.

There is no softdrop except for the T-piece.

derivation

 * 2nd bag J>L

If the Z piece is earlier than the J piece, TST is possible. If the opposite, a double dagger is possible.


 * 2nd bag L>J

TSD is always possible. O-piece, J-piece, and L-piece arrangements are interchangeable.

For further details, please see the "Reference" section.

reference

 * [Sioyaki's Opener Wiki]