Van't Kruijs Opening

The Van't Kruijs Opening, also written Van 't Kruijs, begins 1. e3. It takes its name from Maarten van 't Kruijs, a nineteenth-century Dutch master who took his country's championship title in 1878. Classified as an irregular opening under A00, it opens diagonals for the king's bishop and queen and prepares a later d4, but stakes far less in the center than 1. e4. Black can occupy the middle with ...e5 and ...d5 without difficulty, and the engine rates the position after 1. e3 as level.

The move's main drawback is the queen's bishop, which the e3-pawn shuts in. White must either spend a further tempo on e4, settle for Bd2, or fianchetto with b3 and Bb2. Its main asset is flexibility: with c4 the game can become an English Opening, with d4 a Queen's Pawn Game, with b3 and Bb2 a form of Larsen's Opening, and f4 can lead to Bird-type positions. Benjamin and Schiller described it as a chameleon, and its transpositional range appealed to players such as Aron Nimzowitsch, Bent Larsen and Pavel Blatny.

Black has many sound replies. After 1...Nf6 2. Nf3 play resembles a Réti, and White may continue with d4 or adopt a reversed Hedgehog setup with b3, c4, Nbd2 and Be2. Against 1...e5, 2. c4 gives a reversed Sicilian with an extra tempo for White, while 2. d4 exd4 3. exd4 d5 reaches a French Exchange Variation. A curiosity is 1...e5 2. e4, an Open Game with colors reversed in which Black effectively holds the first move. A kingside fianchetto with ...g6 and ...Bg7 is a common way for Black to cover many transpositions at once.

The named sidelines mostly follow 1...e5. The Bouncing Bishop Variation, 1. e3 e5 2. Bc4 b5 3. Bb3, sees Black offer the b-pawn to drive the bishop back. The Keoni-Hiva Gambit has White play 2. Nc3 and then give up the f-pawn with 3. f4 exf4 4. Nf3; it is split into the Akahi, Alua and Ekolu Variations according to whether Black's second move was 2...Nf6, 2...Nc6 or 2...d5.

The opening is uncommon among grandmasters but very widely played online, ranking among the most frequently reached named positions on Lichess. There, 1...e5 is the most common answer, ahead of 1...d5 and 1...e6, and results are almost exactly even between the two sides.