Kasanari (Stacking) Shogi was inspired by the large, historical Shogi variants with their hundreds of different pieces, using, for the most part, combinations of a few simple directions. The stacking and flipping mechanics of Kasanari Shogi allow you to build myriad combinations using essentially three types of pieces. Serendipitously, the mechanics also give you the ability to have multiple kings, as in the chess variant Gess.

The goal is leave your opponent without a king, either by capturing their last king or by forcing the opponent to split it.

A detailed explanation of the rules, with diagrams, is included in a pdf document. For directions on how to move the pieces, see the Game Description on the Help menu.

Stacks are made up of the pieces "d" (indicating forward movement, away from the player), "p" (backward), "u" (diagonally forward), "n" (diagonally backward), and "z" (sideways). Any stack with exactly one of each of these is a king, emphasized by topping it with a "c" piece (crown). You can have as many kings as you like.

Stacks have "conventional" moves, in which the whole stack moves in any direction indicated by any of the pieces in the stack, up to a distance determined by the number of pieces in the stack with that direction. They can jump over pieces of either side, and can capture when they land.

Stacks can also be reorganized by splitting, joining and flipping. In splitting and joining, the top piece of the moving stack determines the permitted directions of movement. In a split, the top half (rounding down) is moved to an adjacent square, and in a join, the reverse is done: the stack is piled on adjacent stack of the same size, or one larger. The split-join combines these two moves in one. A flip turns over a stack on the first or last rank, providing that makes a change.

Kasanari Shogi was entered in the Stacking Games Contest at rec.games.abstract in 2011.