Kingsrow update

[Ed Gilbert]

It's been a while since I updated kingsrow, but there is a news item at the main page that I will paste here:

9/28/2026: I have built a 12-piece endgame db for English checkers. It's big! And it's available for download. More info here: https://edgilbert.org/EnglishCheckers/1 ... lishDB.htm. There are new versions of Kingsrow (v 1.20) and CheckerBoard (v 1.78) that are needed to use the 12-piece db. Also, I have merged the opening book data for 11-man ballots into the normal Kingsrow opening book. The separate 11-man book file is no longer needed.

[Richard Pask]

A remarkable achievement by someone who, in a broad sense, may legitimately be called one of the greats of the game.

Question 1: do you plan to play any extended 3-move matches between KR 10 and KR 12 and, if so, would you envisage them resulting entirely in draws?

Question 2: do you think KR 12 will have any implications for the 156 ballots or do you think this number is set in stone?

Thank you again for your efforts!

[Ed Gilbert]

Thanks Richard, that is kind of you to say, but in reality it is you that are one of the greats of the game. For me, checkers programming is just a fun hobby.

I have already played thousands of games using the 12pc db, but because they were games played at quick TC (1 sec/m) and with opening books turned off, the games are not all draws. In the last match I ran using the 4-move drawn openings, about 1% of the games were wins or losses. The 12pc db does not start having a big effect on the search until a few moves into the game, so some early mistakes are made.

Question 2: do you think KR 12 will have any implications for the 156 ballots or do you think this number is set in stone?

Definitely no implications, the 3-move ballot questions were settled a long time ago. At this point I feel that the 11-man ballot classifications are also largely settled. I will be surprised if there are any changes there.

[ZoeZap]

Hi Ed, this is great! Would other engines require development work in order to use the new databases?

[Ed Gilbert]

Hi Ed, this is great! Would other engines require development work in order to use the new databases?

No, it works just like the smaller DBs. If you use egdb_identify() it will return a new EGDB_TYPE enum. If your code already keys off the max_pieces returned by egdb_identify, then it will probably work without any changes needed. The set of excluded positions for 11 and 12 pieces is the same as for 9 and 10 pieces.

[johndraughts]

While downloading, I encountered lots of decryption errors and I had to download over and over before I was finally able to download all 24 files for the WLD 12 piece DB. I'm extracting it right now, got about 7 more hours to go, it says there were 2 errors. Hopefully it turns out alright

[Ed Gilbert]

While downloading, I encountered lots of decryption errors and I had to download over and over before I was finally able to download all 24 files for the WLD 12 piece DB. I'm extracting it right now, got about 7 more hours to go, it says there were 2 errors. Hopefully it turns out alright

Since it said there were errors, it's likely that one of the downloaded files is corrupted. The error messages might have told you which file it was. If not, or you can't see the messages now, there are a couple of things that you can do find out which file is corrupted. First, look at all the files with the numbered file extensions (.001, .002, ...) using Windows Explorer. Every one of those files, except for the last one (.023) should have the exact same file size. If that doesn't reveal which file is corrupted, you can open the archive in the 7-Zip File Manager (a free download from https://www.7-zip.org/). Point it at the file with the .001 extension and open it. Then use the "Test" command and 7-Zip will test the integrity of the complete archive and should tell you which one of the numbered split files is corrupted. When you know the offending file, delete it, and then download just that one file again.

-- Ed

[johndraughts]

Thanks Ed. They are all the same size except that last like you said. And they did downloaded correctly eventually after restarting a few times. During the extraction two of the extracted files were noted as having an error. Kingsrow seems to be working with it fine though.

The compressed files is 2.18 TB (2,406,873,037,602 bytes) and the unpacked databases is 2.72 TB (2,999,216,132,096 bytes). A bit off from the 2.88 TB you said it should be, something's not right?

[johndraughts]

Ok here's what I got:

L:\Kingsrow English 2 through 12 pieces WLD db v3\krenglish_wld_v3_setup.7z.001
Data error : krenglish_wld_v3\db11-3314.cpr2
Data error : krenglish_wld_v3\db12-2433.cpr2
CRC failed : krenglish_wld_v3\db12-4242.cpr2

Seems to be the same three errors I got during extraction, when I tested on 7z manager, with the addition of that CRC failed message.

The files are all the same size except the last

[Ed Gilbert]

Johndraughts, it's likely that one or two of your .00x install files are corrupted because of the repeated restarts you experienced during download. I can help you determine exactly which ones you need to get again. Let's move to email so we don't fill up the forum with troubleshooting minutiae. Send me a message at eygilbert@gmail.com