Hippopotamus Defense

1.e4 Nh6

ECO B00

The Hippopotamus Defense is a chess opening reached after 1.e4 Nh6, catalogued under code B00 in the Encyclopaedia of Chess Openings (ECO).

The defining move Nh6 is chosen by Black on move 1.

What is the Hippopotamus Defense?

The Hippopotamus Defense is a chess setup for Black in which the pawns go to a6, b6, d6, e6, g6 and h6 on the third rank, the bishops to b7 and g7, and the knights to e7 and d7, whatever White plays. It can be reached from 1.e4 Nh6, from 1.e4 g6, from 1.d4 b6 and many other first moves, and it is named for the animal that lies low in the water and rises up when disturbed.

It is a system, not a line: Black gives White the whole center and waits, then strikes at it with ...c5, ...f5 or ...d5 once White has committed. Theory rates it as slightly worse for Black, but it has real practical value. It is almost impossible to attack directly, it avoids every opening the opponent has prepared, and Spassky used it twice in the 1966 world championship match against Petrosian without losing. It suits patient counterpunchers and players who want one setup against everything.

How to reach the Hippopotamus Defense

There is no fixed move order. The classical route is 1.e4 Nh6 (the knight later goes to f7 via g8 or supports ...f5) or 1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.Nf3 e6 followed by ...Ne7, ...b6, ...Bb7, ...Nd7, ...a6 and ...h6. Against 1.d4 the same formation arises from 1...b6 or 1...g6. The defining feature is the pawn wall on the third rank with the two fianchettoed bishops behind it; the order in which the pawns and pieces arrive depends on what White threatens.

Pros and cons of the Hippopotamus Defense

Pros

Cons

Main variations of the Hippopotamus Defense

Hippopotamus Defense: classical setup against 1.e4

1.e4 g6 2.d4 Bg7 3.Nf3 d6 4.Nc3 e6 5.Be2 Ne7 6.O-O b6 7.Be3 Bb7 8.Qd2 Nd7 9.Rad1 a6

The full formation against a natural White development. White has d4, e4 and every piece out; Black has the wall and the two bishops behind it. The next moves decide everything: ...h6 and ...g5 for kingside play, ...c5 to hit d4, or ...f5 to hit e4. White's best plan is to prepare a central break, d5 or e5, before Black's breaks arrive.

Hippopotamus Defense: 1.e4 Nh6 (the knight route)

1.e4 Nh6 2.d4 g6 3.Nc3 Bg7 4.Be3 d6 5.Qd2 f6 6.Nf3 Nf7 7.Bd3 e6

The purest move order: the knight goes to h6 at once and, after ...f6, reroutes to f7, where it supports ...e5 and ...g5 ideas and keeps the g7-bishop's diagonal open. White's most direct answer is Be3 and Qd2, hitting h6 and preparing long castling and a pawn storm.

Hippopotamus Defense: the ...c5 break

1.e4 g6 2.d4 Bg7 3.Nc3 d6 4.Be3 a6 5.Qd2 b5 6.f3 Bb7 7.Nge2 Nd7 8.O-O-O c5

Black's main lever against a big center: ...c5 attacks d4 and, after ...cxd4, opens the c-file and the long diagonal for the g7-bishop. Combined with ...b5 and ...Nb6 it gives Black queenside play against a queenside-castled king, the Hippopotamus at its most aggressive.

Hippopotamus Defense: the ...f5 break

1.e4 g6 2.d4 Bg7 3.Nf3 d6 4.Nc3 e6 5.Bc4 Ne7 6.O-O h6 7.Be3 Nd7 8.Qd2 f5

The kingside lever: ...f5 attacks e4 and opens the f-file for a rook. It is the break Spassky used, and it works best when White has castled short and the e7-knight can recapture on f5. After exf5 exf5 Black gets central pawns and open lines; White gets the e-file and the weakened black king.

Hippopotamus Defense against 1.d4 (via 1...b6)

1.d4 b6 2.c4 Bb7 3.Nc3 e6 4.e4 g6 5.Nf3 Bg7 6.Bd3 d6 7.O-O Ne7 8.Be3 Nd7

The same wall against the queen's pawn, reached through the English Defense move order. White has a broad center with c4, d4 and e4; Black's breaks are ...c5 and ...f5 as usual, and the c4-pawn gives an extra target for ...Nc6-a5 or ...d5 ideas.

Hippopotamus Defense: White's central break (d5 or e5)

1.e4 g6 2.d4 Bg7 3.Nf3 d6 4.Nc3 e6 5.Be2 Ne7 6.O-O b6 7.d5 e5 8.Nd2 f5 9.f4 Bb7

White strikes first with d5, closing the center and fixing the structure before Black's ...c5 or ...f5 lands, then plays for f4 and the kingside or c4-c5 on the queenside. Black answers ...e5 and ...f5 for a King's Indian-type battle. The timing of this break is the whole fight against the Hippopotamus.

How to play against the Hippopotamus Defense

Do not attack the wall; use the space. The Hippopotamus gives White the center for free, so the plan is to develop naturally, castle, and choose a central break before Black's own break arrives: d5 to fix the structure and follow with f4 and a kingside advance, or e5 to open the e-file when the e7-knight is badly placed. The h6-pawn and the slow kingside make a g4 and h4 pawn storm with queenside castling a serious option, especially against the 1.e4 Nh6 move order where Be3 and Qd2 hit h6 at once. What fails against the Hippopotamus is impatience: premature sacrifices or an early pawn storm without development run into the ...c5 and ...f5 counters, and then the extra space becomes a liability. Build, then break.

Plans for both sides

White's plan

Take the center with d4 and e4 (and c4 against the 1...b6 order), develop every piece, and pick the break, d5 or e5, before Black plays ...c5 or ...f5. Against a slow setup, castle long and storm with g4 and h4 against the h6-pawn; against a fast ...c5, keep the center with c3 or dxc5 and use the space on the queenside.

Black's plan

Complete the wall and the two fianchettoes before doing anything, then choose the break by White's setup: ...c5 against a long-castled king or a d4 without c3 support, ...f5 against a short-castled king with e4 unsupported, ...d5 or ...e5 when White has overextended. Keep the knights flexible on e7 and d7 and never leave the king in the center after the breaks.

History of the Hippopotamus Defense

The setup was analyzed by the Slovak master Maximilian Ujtelky in the 1950s and 1960s, who played it against everything, and it was named the Hippopotamus for its habit of lying low in the water and rising up when disturbed. Its finest hour came in 1966, when Boris Spassky used it in games 12 and 16 of his world championship match against Petrosian and drew both. Since then it has been a favorite of surprise-seeking players at club level and an occasional weapon in rapid play; Carlsen and Nakamura have both tried it online.

Hippopotamus Defense FAQ

Is the Hippopotamus Defense good?

It is playable but slightly inferior: White gets the center for free and a small edge with a well-timed d5 or e5. Its value is practical, as a low-theory system that avoids the opponent's preparation and is hard to attack, and Spassky drew twice with it in a world championship match.

What is the Hippopotamus setup in chess?

Pawns on a6, b6, d6, e6, g6 and h6, bishops on b7 and g7, knights on d7 and e7, the king castled short. Black completes the formation whatever White plays and then breaks with ...c5, ...f5, ...d5 or ...e5.

How do you beat the Hippopotamus Defense?

Take the center, develop fully, and break with d5 or e5 before Black's own break arrives, or castle long and storm the h6-pawn with g4 and h4. Do not sacrifice early; the wall is designed to punish impatience.

Did Spassky play the Hippopotamus?

Yes. Boris Spassky used it in games 12 and 16 of his 1966 world championship match against Tigran Petrosian and drew both, which is the opening's best-known endorsement.

What is the difference between the Hippopotamus and the Modern Defense?

The Modern Defense (1...g6 and ...Bg7) is the starting point; the Hippopotamus adds the second fianchetto with ...b6 and ...Bb7, the pawns on e6 and d6 and both knights on the second rank. A Modern player usually strikes at the center earlier with ...c5 or ...e5; the Hippopotamus waits until the full wall is built.

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