Designed and made by Minoru Abe 1985, directions in Japanese.
(cardboard box, wood tray, and 12 painted wood pieces, 5.25 by 6.25 by 3/4 inches)

Mass produced version, purchased 2018. (cardboard box, 12 painted pieces with raised lettering, directions in Japanese, 5.25 by 6.25 by 3/4 inches

Made by J. A. Storer 2007. (cardboard sleeve, Bloodwood tray, fixed 1x1's, Birdseye Maple WHITE, Rosewood BLACK, unknown hardwood L's, plexiglass keeper, 5 by 6 by 3/4 inches)

The two blank 1x1 pieces are glued to the tray and cannot move. The center blank 2 by 1 keeper piece is removed to make the starting position shown on the right above. The goal is to slide the pieces so that BLACK is on top and WHITE is on the bottom.

Hordern's book shows 198 rectilinear (237 straight-line) moves and the Puzzler's Tribute book, in a chapter coauthored by Minoru Abe, shows 190 rectilinear (231 straight-line) moves.

Here are the start position, end position, and the positions of Hordern's solution for which an L-shaped piece is to be moved next:

We use a more verbose notation than Hordern's book. The first letter is the piece to be moved (X denotes the left L-shaped piece and Y the right one) and the second letter is the direction; all moves are a distance of 1 unit unless followed by a 2 (to specify two units). Two consecutive moves of the same piece are listed together as a single rectilinear move.


(198 rectilinear moves, 237 straight-line moves)

Here are the start position, end position, and the positions of Puzzler's Tribute solution for which an L-shaped piece is to be moved next:

We use the same notation as we did for the Hordern solution (like Hordern's book, the Puzzler's Tribute book uses a more compact notation than is used here). The first letter is the piece to be moved (X denotes the left L-shaped piece and Y the right one) and the second letter is the direction; all moves are a distance of 1 unit unless followed by a 2 (to specify two units). Two consecutive moves of the same piece are listed together as a single rectilinear move.


(190 rectilinear moves, 231 straight-line moves)