The Hippopotamus Attack is a variation of the Formation, catalogued as ECO A00. The line runs 1. a3 e5 2. b3 d5 3. c3 Nf6 4. d3 Nc6 5. e3 Bd6 6. f3 O-O 7. g3, reaching the position shown below after 13 half-moves.
Black holds the centre with pawns on d5 and e5. Black is ahead in development, with three minor pieces out to White's zero. It is Black to move after seven moves. Black has castled while White’s king is still uncommitted.
On the Formation generally: ECO A00. A chess opening with 2 known variations.
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The Hippopotamus Attack goes 1. a3 e5 2. b3 d5 3. c3 Nf6 4. d3 Nc6 5. e3 Bd6 6. f3 O-O 7. g3. It is a variation of the Formation and is catalogued as ECO A00.
The Hippopotamus Attack is ECO A00. ECO codes group openings by their move order, so nearby codes cover closely related lines of the Formation.
Stockfish evaluates the position after 1. a3 e5 2. b3 d5 3. c3 Nf6 4. d3 Nc6 5. e3 Bd6 6. f3 O-O 7. g3 at -2.03 at depth 18, which is a clear advantage for Black. Engine evaluation is only a starting point — at club level the practical value of a line is mostly about whether you know its plans better than your opponent does.
Black holds the centre with pawns on d5 and e5. Black is ahead in development, with three minor pieces out to White's zero. It is Black to move. Black has castled while White’s king is still uncommitted.