Deep Sjeng 3.x

Deep Sjeng 3.x is the third incarnation of the Deep Sjeng engine. It significantly improves upon the strengths of the Deep Sjeng 2.x engine, bringing faster, deeper search, longer-range planning and an enhanced understanding of active piece play, as well as more endgame knowledge. The result is a cut-throat chess opponent and analysis partner with a great understanding of dynamic compensation. Deep Sjeng 3.0 is about 100 ELO stronger than Deep Sjeng 2.7.

Deep Sjeng WC2008 is an enhanced version of Deep Sjeng 3.0 that is the World Computer Speed Chess Champion 2008. It is a free upgrade for Deep Sjeng 3.x and is included with the package for new customers.



Deep Sjeng 3.x is no longer for sale.

Download Deep Sjeng WC2008 update (only for previous customers).

Frequently Asked Questions

What is the ideal hash size for blitz/bullet/long games?

Deep Sjeng uses an optimized hash table implementation that can make full use of any memory you give it. So the answer is always: as much as possible! Of course you should not allocate so much memory that your machine starts swapping to disk. A good guideline is to allocate half the amount of RAM you have, or one third if you play engine-engine matches. Deep Sjeng itself has no problems to play 1 minute games with 2Gb of hash.

Does Deep Sjeng 3.x come with an opening book?

No opening book is included for now. In general Deep Sjeng plays all openings well and works fine with the free books you can find on the internet. However we will probably make a book available later on which emphasises the active style of the engine. Please check back the website regularly.

How do I enable Nalimov endgame databases?

During testing of Deep Sjeng 3.x we found that the advantage of endgame databases is often grossly overstated and there is in reality essentially no benefit. Particularly on a loaded machine or on a laptop they might even make chessprograms play worse! So we made the decision to remove EGTB support from Deep Sjeng 3.x and instead implement as much endgame knowledge as possible directly into the engine. The result is that the engine is now much stronger in the late middlegame (where EGTB cannot help much), at the expense of very seldomly allowing a won game to be drawn or a drawn game to be lost in the deep endings. In Deep Sjeng WC2008 tablebase support was re-added for customers that require it for deep endgame analysis.

Why should I buy a bare engine without a GUI?

All chessprograms are so strong nowadays that even free programs are good enough to beat all chessplayers. However, for analyzing games it is essential to have strong engines available with different playing styles. They can help you by suggesting alternate plans possible in a position. Deep Sjeng is such a strong engine with a very particular playing style. Additionally, you can configure Deep Sjeng to play at your ELO level, so you get a perfectly matched opponent.

Do you have some examples of the playing style?

In the 8th International CSVN Tournament Deep Sjeng thrashed a strong field of engines to take second place, just half a point behind Rybka running on much faster hardware. You can find the games here: ICT8 Tournament PGN

Can I use Deep Sjeng 3 with WinBoard/ICC/

Yes! The Dasher interface supports Deep Sjeng in UCI mode directly for analysis and playing. Consult the Dasher help for instructions. To play on the server, you can use WinBoard with Polyglot. An example Polyglot configuration file is here as well as a book.