Licenses and attribution
Credits
Professor Orin includes open-source software, an attributed puzzle dataset, and a pinned chess network. The notices below describe the third-party material identified in the current shipping build.
Arasan chess engine
Professor Orin uses Arasan v26.0, pinned to upstream commit d8613aca11b3db15ce7f5c6d54da4dc4b31f63f8. Copyright 1994–2026 by Jon Dart. Arasan is distributed under the MIT License.
Arasan neural-network file
The app bundles arasanv8-20260622.nnue from Arasan v26.0. Its SHA-256 is b42f9e13a37debb4af425d2ca74b5edff1d8034a616806bccdb67b79530201ac.
Upstream describes the network as trained from a combination of Arasan self-play and LCZero training data. The exact LCZero input identifiers or manifest have not been published, so Professor Orin records that manifest as pending third-party documentation and does not describe the provenance as more complete than the upstream record.
Lichess puzzle data
Professor Orin bundles attributed positions from the Lichess open puzzle database, which Lichess releases under CC0. Imported positions preserve their puzzle identifiers and source-game links inside the app. Separately labeled local pattern drills are original Professor Orin teaching positions.
PostHog analytics SDK
The app includes PostHog iOS SDK 3.70.1, distributed under the MIT License. Professor Orin configures it for the limited product analytics described in the Privacy Policy.
Attribution or rights concern
If you believe an attribution, license notice, or rights statement is incomplete or incorrect, email support@orin.games with the relevant material. We will investigate the concern and correct verified omissions promptly.