Our contribution are the following features:
- Included Threefold repetition rule using Compact Chess Representation of history boards (C.C.R.) , we made it valid for the last 15 boards with 32 bytes per board; so the history boards occupies 480 bytes of RAM.
- Included the Fifty-move rule check (from fairy-Max ).
- For instance, the 32-bit test version of Rybka on AMD 64-bit CPU running on 2.4Ghz achieves 104 Knps (thousands of nodes per second) .
- The ATmega328P ChessMate at 25 MHz approach, can reach ~ 1.3 Knps (1298.1 nodes/s).
A node refers to a branch of play the computer investigated.
The following figure shows the nodes investigated versus move number (the engine was playing against itself):
FIGURE A1 - Nodes versus Move number (Chess engine playing against itself)
This table refers to the FIGURE A1 at Level 6 (Recursion Limit =1000)
|Move||Thinking time (ms)||Nodes (depth)|
 - Micro-Max, a 133-line Chess Source
 - Vladan VUCKOVIC, "AN ALTERNATIVE EFFICIENT CHESSBOARD REPRESENTATION BASED ON 4-BIT PIECE CODING"
 - Fairy-Max: an AI for playing user-defined Chess variants