Build an opening repertoire with uncharted variations using the power of the strongest chess engine and the wisdom of chess grandmasters FEATURES - Offline implementation — Arkon does not use cellular data - Moves scored by powerful Stockfish chess engine in centipawns (cp) - Move popularity from Chess Grand Master games (ELO 2600+) - Game PGN chess position display and export via email - Opening Lines from Encyclopedia of Chess Openings (ECO) SUPPLEMENTAL CONTENT Arkon is free to download and use. However, should you desire to explore chess openings beyond the first 20 positions, you can unlock a full version as follows: 3-Month Unlimited Moves: USD 0.99 1-Year Unlimited Moves: USD 2.99 Lifetime Unlimited Moves: USD 8.99 All of these purchase items have unrestricted access to explore openings regardless of move depth