Mikenas Defense

The Mikenas Defense answers 1. d4 with 1...Nc6, developing the queen's knight at once and preparing ...e5. It also goes by the Bogoljubov–Mikenas Defense, the Queen's Knight Defense and the Lundin Defense. The move is committal because it blocks the c-pawn, a piece Black normally keeps flexible against 1. d4. Part of the idea mirrors Alekhine's Defense on the other wing: Black invites White to gain space with pawn advances, intending to counterattack the extended center later.

Much of the time the game leaves the opening's own territory. In the Lichess database 2. e4 is by far the most frequent reply, and it reaches the Nimzowitsch Defense, more often reached via 1. e4 Nc6 2. d4. After 2. c4 d5 the position is a Chigorin Defense to the Queen's Gambit. 2. Nf3 stops ...e5 directly, and 2...d5 then gives a Queen's Pawn Game in which Black's early knight development is unusual. After 2. Nf3, 2...d6 can head for Pirc or King's Indian structures, while 2...e6 can reach Nimzo-Indian, Bogo-Indian or Chigorin positions if White follows with c4. 2. Bf4 is another practical option.

The lines specific to 1...Nc6 begin when White drives the knight back with d5. The immediate 2. d5 usually sends it to e5, a line Sid Pickard called the Bozo-Indian Defense, despite the absence of ...Nf6. More often the push comes after 2. c4 e5 3. d5. White then has a space advantage, and the knight must choose a square. The Lithuanian Variation, 3...Nce7, retreats it to e7. From there it can support a kingside setup. The Cannstatter Variation, 3...Nd4, centralizes it on d4, an active but exposed post. White can instead take on e5: the Pozarek Gambit, 2. c4 e5 3. dxe5 Nxe5 4. Nc3 Nxc4, offers the c-pawn for a lead in development.

Aron Nimzowitsch and Efim Bogoljubov experimented with the defense, but it has never gained wide acceptance. Engines give White a slight edge and rate 2. d5 as the most testing reply. White scores somewhat better in practice, and draws are rare.