About Bobail
How to Play
Bobail is a game played on a 5x5 grid. One player controls white, and the other, black. Each player's turn consists of the following steps:
1. Move the bobail (the yellow piece). This piece moves like a king in chess. One square in any direction.
2. Move your color piece (black or white). These pieces move in any direction, but they have to move as far as possible. So it's kind of like a queen in chess, except she's on slippery ice and only stops when she runs into another piece or the edge of the board.
Each player must do step 1 followed by step 2. Both steps must be done (there is no passing your turn). The only exception is on the very first turn, white does only step 2.
There are no captures, ie all the pieces always remain on the board.
Winning conditions:
1. Move the bobail to your home row. More specifically, if the bobail ever makes it to the bottom row, white wins. If the bobail makes it to the top row, black wins.
OR
2. Trap the bobail. If you trap the bobail so that on the other player's move she cannot move it, then you win.
Game History
Bobail is a variation of the game Neutron. Neutron was invented in 1978 by Robert A. Karus. Bobail is identical to Neutron except that in Neutron, the bobail piece moves like every other piece (a queen on ice).
And as with so many other games on this website, I first found out about it in my new favorite book: Math Games with Bad Drawings.
About the AI
The AI first tries to find a win through minimax with alpha beta pruning, but using only a shallow depth. Then, assuming a win isn't found, it switches to a Monte Carlo Tree Search method. Currently the AI is pretty strong -- even on its lowest setting (thinking for .01 seconds) I personally cannot beat it consistently 😣