Natwarlal is my chess program. It is a chess engine, and does not have a GUI of its own. However, it is compatible with the well known chess GUIs - Winboard (Xboard for Linux) and Arena. I have created a installable package with both Natwarlal and Winboard already set up. If all you want to do is play chess with Natwarlal, you can download the installer.

A command line version without winboard is also available for people who already have Winboard or Arena. There is a readme file included with the engine which describes how to set up Natwarlal with Winboard and Arena.

Natwarlal is a challenging chess engine. I estimate it plays around 2100 ELO. That means that Natwarlal will beat nearly all humans, and quite a few other chess engines. However, strong human players should be able to beat it. I have never played with Natwarlal, although I don't think I can beat it :) If you have a fast computer, Natwarlal will play a bit stronger. If it is too strong for you, it is possible to weaken Natwarlal. See the readme file included with the engine for details.

Natwarlal can also analyze your chess games for you. It can also help you improve your chess play. Just set up a position in Winboard or Arena, and let Natwarlal analyze it. You can even load a full game (PGN file) in Winboard/Arena, and go over it move by move, with Natwarlal analyzing each move.

Comments, bug reports are welcome, and can be sent to pallavnawani[at]yahoo[dot]com

• Aspiration windows
• Negamax Alpha-beta search with PVS
• Separate move ordering for qsearch, normal search & root search
• Double transposition tables, also used in move ordering
• Pawn hash tables
• 8x16 chessboard (0x88 Method)
• Simple eval function with very basic pawn structure evaluation and king safety evaluation.
• Winboard protocol 2, should also work with Winboard protocol 1.
• Search extensions
• Pondering
• Analysis mode
• Stop and go
• Quiet search (Also called quiescence search).
• Coordinate notation move input/output (Also called long algebraic notation).
• Setting boards using FEN.
• Supports time controls
• Null moves
• Depth reduction, futility pruning
• Opening book
• Book creation, although the procedure is a bit messy.
• Can resign if it is losing
• Detects repetition draws, 50 move rule draw, some material draws.

Latest version of Natwarlal is 0.09. Both the executables and the source code is available. You can also download some games played by Natwarlal. These are zipped PGN files. Both Winboard & Arena (and Xboard for linux) allow you to playback these games. These games are Natwarlal vs Golem, Natwarlal vs Mscp, and one really clever draw that Natwarlal (Version 0.01) played with Beowulf. I have described that game in more detail below.