Chess engines for analysing games

Question

Up untill now, I have used Rybka for analysis of my games. What other chess engines have you used, and how helpful are they?

I am not interested in a list of chess engines with their respective websites, the name of an engine you have just heard of. I want a fact-based review from someone who has used the engine mentioned in their answer for a long time, and found and helpful.

What I am looking for in the mentioned engine is to find a way to calculate the accuracy of the game:

• How often the player was making good moves.
• How often the advantage in the game was changing

Previously I saw such options in Rybka, but in my current version Rybka v4, I cannot see this option as available.

Many thanks to @ETD for a helping hand in giving a direction on what exactly I want in an answer.

Answer 1

I use Stockfish, and have found it useful for analysis largely because of its multipv support (I switched from Crafty a couple of years ago), and it being free. I feel it lacks EGTB support, so it's not up to par with Rybka in that respect, but haven't felt willing to shell out the money for Rybka yet, just for that feature. It sounds like it also might do a better job of reporting forced draws, but I haven't confirmed that myself.

I agree with Ed, you should give guidance on what you want to hear in your answers. Rybka is a fine analysis engine.

Answer 2

Here's an obligatory post about the benefits of Rybka...

The biggest advantage to Rybka (especially Rybka 4) is that it has a very good positional understanding. It is capable of giving a fairly accurate assessment of the initiative and king safety, subject to the same limitations of all other chess engines.

Generally speaking, I find that Rybka is slightly slower tactically than Houdini or Stockfish, but that the positional "understanding" more than makes up for this weakness. Granted, Rybka and I work well together and that's a personal preference, but I have tried all of the major engines in some tricky positions and Rybka always seems to make me more productive.

Answer 3

Chess engines all work in a similar way, but Graphical User Interfaces(GUIs) report this info in different ways. Chessbase produces GUIs based on Fritz which show a little engine window with a number, plus if white is winning or minus if black is winning. Chessbase GUIs also have a little light that flashes red when one side's move was a blunder. This Chessbase line of GUI/engine combos includes Komodo 9, Houdini 4, Rybka 4 and Deep Fritz 14. The GUI part in each case is the same. You can buy just the engine, or download a free engine like Stockfish, and plug it into a GUI that you have.

A lot of GUIs do full game analysis, both commercial - Aquarium, Chessmaster, Chess Assistant, Shredder(in its own or a Chessbase GUI) and Hiarcs Chess Explorer - as well as free alternatives, Arena, SCID and SCID vs. PC. Automatic game analysis does highlight certain turning points in each game, but you probably learn more by going through the game yourself with the engine running, and exploring different lines to see what happens.

Individual engines have their own quirks. Rybka had an excellent feel for material imbalances and sacrifices, but it has problems with certain endgames seeing an advantage in theoretically drawn positions. Komodo 9, Stockfish 6 and Houdini 4 all benefited from Rybka's ideas, and their latest versions are stronger than Rybka 4. Komodo and Houdini are perhaps a bit more conservative than Rybka, while Stockfish has a different style from the others. For a regular player just trying to improve his game, all these engines are going to seem pretty similar though, and a lot of the time they recommend the same moves.

Engines in general have trouble with long term planning and evaluating endgame positions. They often pursue short term material gain, while ignoring long term weaknesses like king safety, weak colour complexes and pawn structure. Engines are very strong at tactics though.

Answer 4

I would strongly recommend Stockfish. My reason for this is that it is the strongest open source engine that ia currently available. Being open source, you can not only work out how it evaluates, but also modify its code to suit your style and needs. It's very easy to install, build and use.