Custom computer game

Hi,

How can I setup a custom game against computer or get computer analysis from a custom position in V3 Web?

For instance I want to play this against computer in coach mode.

 You can't. That's what you have to get a chess engine for. (You could also look it up in a tablebase.)

OK, thanks 

Yes, You can custom computer game on chess.com by editing the URL

Example in V3

https://www.chess.com/play/computer?fen=rknnrqbb%2Fp1ppp1pp%2F1p6%2F5p2%2F5P2%2F1N2N3%2FPPPPP1PP%2FRK2RQBB%20b%20EAea%20f3%200%203&is960=1

https://www.chess.com/play/computer?fen=rknnrqbb%2Fp1ppp1pp%2F1p6%2F5p2%2F5P2%2F1N2N3%2FPPPPP1PP%2FRK2R1BB%20b%20EAea%20f3%200%203&is960=1

lower case - black

upper case - White

 %2F - between rows, row go a to h

p - pawn

number mean how many saquer empty in that row

 https://www.chess.com/play/computer?fen=nnnknnn%2FnnnKnnnn%2F8%2F8%2F8%2F8%2FNNNNNNNN%2NNNKNNNN%20b%20EAea%20f3%200%203&is960=0

 Thanks for your answers. For interested, here is the link for this situation. 

White to move:

https://www.chess.com/play/computer?fen=8%2F8%2F7p%2F6p1%2F3k2K1%2F6P1%2F8%2F8%20w%20EAea%20f3%200%203&is960=1

Black to move:

https://www.chess.com/play/computer?fen=8%2F8%2F7p%2F6p1%2F3k2K1%2F6P1%2F8%2F8%20b%20EAea%20f3%200%203&is960=1

Thanks for these examples... I tried this successfully (and set up a ruy lopez open for practice); however, I found there is a bug... It will NOT allow a castle, either side???   Any ideas/help?

Here is my setup:

Ruy Lopez:

Black Turn:
https://www.chess.com/play/computer?fen=r1bqkbnr%2F1pp2ppp%2Fp1p5%2F4p3%2F4P3%2F5N2%2FPPPP1PPP%2FRNBQ1RK1%20b%20EAea%20f3%200%203&is960=1

White to move:
https://www.chess.com/play/computer?fen=r1bqkbnr%2F1pp2ppp%2Fp1p5%2F4p3%2F4P3%2F5N2%2FPPPP1PPP%2FRNBQK2R%20w%20EAea%20f3%200%203&is960=1

...Also, the program dies after ~9 moves...  What gives????

I don't play the computer, but I think I know what's happening. It appears you're using the Chess960 format, but your position is a standard chess position? That's OK, it should still work with one change. In the URL strings, try changing EAea to HAha.

[EDIT] - Oops, I missed one thing. In the first URL (Black Turn), replace EAea with ha, NOT HAha.

At the risk of causing complete confusion, if your intent is to play regular chess and not Chess960, I think the modified URLs for your two positions in V3 would be:

Ruy Lopez:

Black Turn:

https://www.chess.com/play/computer?fen=r1bqkbnr%2F1pp2ppp%2Fp1p5%2F4p3%2F4P3%2F5N2%2FPPPP1PPP%2FRNBQ1RK1%20b%20kq%20f3%200%203&is960=0

White to move:

https://www.chess.com/play/computer?fen=r1bqkbnr%2F1pp2ppp%2Fp1p5%2F4p3%2F4P3%2F5N2%2FPPPP1PPP%2FRNBQK2R%20w%20KQkq%20f3%200%203&is960=0

Actually, I think I spotted another couple of mistakes. Looking at the two positions, I don't think they should be specifying an en passant square, and although it may not be too important, the halfmove clock and fullmove numbers are incorrect. So the correct URLs should be:

Ruy Lopez:

Black Turn:

https://www.chess.com/play/computer?fen=r1bqkbnr%2F1pp2ppp%2Fp1p5%2F4p3%2F4P3%2F5N2%2FPPPP1PPP%2FRNBQ1RK1%20b%20kq%20-%201%205&is960=0

White to move:

https://www.chess.com/play/computer?fen=r1bqkbnr%2F1pp2ppp%2Fp1p5%2F4p3%2F4P3%2F5N2%2FPPPP1PPP%2FRNBQK2R%20w%20KQkq%20-%200%205&is960=0

Thanks much EscherehcsE for the review and recommendations!

You have made some statements regarding changing Eaea to HaHA etc...  Is this documented somewhere?  Do you have a link?  I'd like to read what the URL requirement rules actually are...  Thanks

EscherehcsE

Did you try the links in my Post #11? Did they actually work? (I didn't try them myself, and I'm curious to know the results.)

Based on Posts 4 & 5, it looked to me that V3 was using the Shredder FEN format for Chess960 castling notation, so I just ran with that idea. (If you're specifying the standard non-Chess960 setup, I wasn't sure if you should specify HAha or KQkq for the castling notation.)

Anyway, here's a few links to skim:

1) For the FEN standards for normal chess, see Section 16.1 of this spec - http://www.saremba.de/chessgml/standards/pgn/pgn-complete.htm

2) For Chess960, try this link (especially the section titled "Coding games and positions" - https://en.wikipedia.org/wiki/Chess960

For the Shredder FEN format, to create the castling notation, you basically use the file letters that the rooks initially occupy. Capital letters signify the White pieces, and lower case letters signify the Black pieces. For example, since the normal chess position has the two rooks on files a and h, the castling notation would be HAha. (The higher letter is always mentioned first.) As a second example, if you had a Chess960 position where the rooks were initially positioned on the b-file and the g-file, the castling notation would be GBgb.

I tried the URLs in Post #11, and they do work. So, you should be able to enter just about any starting position you desire. If you're having a hard time generating the FEN info, you could always enter the starting moves into Arena, then grab the FEN of that position. Then all you'd have to do is shoehorn the FEN info into the Chess.com computer's URL structure.

The only caveat with Arena is that it doesn't use Shredder FEN castling notation for Chess960 games. Instead, it uses the standard KQkq notation, which is not desirable for Chess960. If you're setting up a Chess960 game in Arena, you can actually enter a board position and tell it which of the 960 positions to use. (Or, you can scroll through the 960 positions, and it will graphically show you the piece arrangements for each position.) Once you've entered the Chess960 position into Arena, then you can tell Arena to give you the FEN for that position. Keep in mind that the FEN that Arena gives you will be using the incorrect KQkq castling notation, so you'll have to manually change it to the proper Shredder FEN notation (for example, GAga, or FBfb, etc., whichever file letters the rooks are on at the beginning of the game).