Kangaroo Defense

The Kangaroo Defense arises after 1. d4 e6 2. c4 Bb4+. It is also known as the Keres Defense, after the Estonian grandmaster Paul Keres, and as the Franco-Indian Defense. Black develops the dark-squared bishop with check before committing the king's knight. White must decide at once how to block the check, often before choosing between Nc3 and Nf3, while Black keeps the choice of a French-style ...d5 or an Indian setup with ...Nf6 open.

White has three ways to meet the check: 3. Bd2, 3. Nc3 and 3. Nd2. Reference theory treats 3. Bd2 as the standard reply, though in the Lichess sample 3. Nc3 is played slightly more often. The engine slightly prefers White in the starting position and lists all three moves as its top choices. Against 3. Bd2, Black can exchange with 3...Bxd2+, reaching a line of the Bogo-Indian. A second option, 3...a5, keeps the bishop on b4 and usually becomes a Bogo-Indian once White plays Nf3. Black can also allow White a broad center with 3...Qe7 4. e4 d5, hitting the e4-pawn at once instead of preventing its advance.

The interposition 3. Nc3 is catalogued as the Transpositional Variation, because the knight on c3 under the pin points toward Nimzo-Indian positions once Black adds ...Nf6. The rarer 3. Nd2 avoids the pin and the doubled c-pawns that ...Bxc3 could cause, at the cost of a less active knight. In all these lines the play depends on the structure. Black aims for pressure on the dark squares and on e4 rather than an early fight in the center.

The opening sits in the middle range of named openings by frequency. It serves mostly as a move-order device for players who already know the Bogo-Indian or Nimzo-Indian and want to keep White guessing. In online games White scores better than Black, and draws are uncommon.