Shogi

The board is nine squares by nine, each player starts with twenty pieces, and the pieces are flat wedges with the name written on them rather than carved shapes. Both sides face the same direction, so ownership is shown by which way a piece points. Capture something and it goes to your hand, and on any later turn you can drop it back onto almost any empty square as your own.

That single rule changes everything. Chess simplifies as it goes and heads towards endgames with few pieces left. Shogi never simplifies, because material never leaves the board, and the attack usually ends in a mating net built from dropped pieces rather than a slow grind. Most pieces also promote once they reach the far three ranks, flipping over to show a red character on the back.

The professional scene is a career with newspapers and sponsors behind it. Habu Yoshiharu held all seven major titles at once in 1996. Fujii Sota turned professional at fourteen and won his first title at seventeen. March Comes In Like a Lion built an entire series around what that life does to a teenager who is good at it.