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Show HN: OffChess – Offline chess puzzles app

(offchess.com)
344 points avadhesh18 | 5 comments | 08 Jul 25 08:57 UTC | HN request time: 0.799s | source

Hi HN!

I'm the developer of rdx, a mildly popular ad-free, privacy and user friendly Reddit client. This time, I made something for a very specific use case: solving chess puzzles with no internet.

Why? Well, my Wi-Fi is terrible in the bathroom—and that's where I do some of my best thinking. I tried printing out “mate in X” puzzles to solve offline, but they weren’t fun without interaction. So I built OffChess.

OffChess is an iPhone/Android app that contains over 100,000 chess puzzles, fully offline and completely ad-free. You can solve puzzles by category (Mate in 1/2/3/4/5, tactics like pins/forks/skewers, or openings like Sicilian/French, etc). You gain or lose points based on how you perform, so there's a light rating system to keep things engaging.

No accounts, no tracking, no monthly subscriptions, no internet required. Just pure, old-school tactical chess training, wherever you are.

You can check out the iPhone/iPad app at https://apps.apple.com/us/app/chess-puzzles-offchess/id67447... or the Android app at https://play.google.com/store/apps/details?id=com.offchess

Would love feedback, bug reports, or suggestions.

Thanks!

1. tdiff ◴[08 Jul 25 13:52 UTC] No.44499980[source]▶
I wonder where were those 100k puzzles sourced from?
replies(2): >>44500178 #>>44501760 #
2. GCUMstlyHarmls ◴[08 Jul 25 14:11 UTC] No.44500178[source]▶
TacticsMaster on F-Droid also says it has 100k puzzles, sourced from https://database.lichess.org/#puzzles, though that says it has 5 million puzzles, so perhaps 100k is just a coincidence, a nice number, or maybe of the 5m there's a nice subset.

> Generating these chess puzzles took more than 100 years of CPU time.

The page includes a link to the puzzle generator and tagger for interests sake.

replies(1): >>44502929 #
3. binarymax ◴[08 Jul 25 16:50 UTC] No.44501760[source]▶
Not OP but generating puzzles isn’t hard if you have a database of games and I’ve done it myself.

For each game just fast forward to the end and ask for Stockfish to provide the solution. If it’s guaranteed “mate in X” then you’ve got yourself a puzzle. You can have a classifier that grabs other puzzle types too (“win the queen in X” for example)

replies(1): >>44506367 #
4. pncnmnp ◴[08 Jul 25 18:59 UTC] No.44502929[source]▶
To add to this thread, here's how Lichess generates chess puzzles - https://github.com/ornicar/lichess-puzzler
5. zippyman55 ◴[09 Jul 25 04:30 UTC] No.44506367[source]▶
At scale, It gets a little harder trying to explain the solution. There is often a combinatorial explosion of move possibilities, so it’s not easy to just say MATE IN 4 if there are 40 or 50 potential responses all leading to mate. Granted they are obvious mates but there may be users who do not see the obvious mates.