Agincourt Defense, Neo-Catalan Declined, Early b3

The Early b3 is a move-order branch of the Neo-Catalan Declined. White plays 5. b3 before castling, preparing Bb2 and a Réti-style double fianchetto instead of committing to an early d4. Black most often castles with 5...O-O. The engine also favors the central advance 5...d4 and the more active 5...c5, and it judges the position roughly balanced. In online games White scores somewhat better.