Gunderam Defense: 5...Bf5 with 6.Ne5 and g4

Black develops 5...Bf5 to control the diagonal. White centralizes the knight to e5 and launches the g4 and h4 pawn storm to trap the misplaced bishop.

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bf5 6.Ne5 e6 7.g4 Bg6 8.h4

Move by move

1.d4 – White opens with 1.d4: firmly staking a claim in the center, governing key squares c5 and e5, and opening paths for the light-squared bishop.
1...d5 – Symmetrical central answer 1...d5: Black anchors a pawn firmly in the center to dispute territory and avoid early space concessions.
2.e4 – The Blackmar-Diemer Gambit begins with 2.e4: a bold strike aimed at deflecting Black's d5-pawn and opening vicious attacking lines.
2...dxe4 – Accepting the gambit 2...dxe4: Black pockets the central pawn, ready to defend the material gain with careful and precise play.
3.Nc3 – Aggressive development 3.Nc3: the knight immediately attacks the advanced e4-pawn, stepping up pressure on Black's central outpost.
3...Nf6 – Natural defense 3...Nf6: Black mobilizes the knight toward the center, solidly defending the extra pawn on the contested e4-square.
4.f3 – The conceptual heart of the gambit 4.f3! White offers a second pawn to blow open the f-file and accelerate piece mobilization.
4...exf3 – Forced capture 4...exf3: Black accepts the second pawn sacrifice, but gifts White a powerful and completely open f-file for the rook.
5.Nxf3 – Active recapture 5.Nxf3: the knight leaps into action with dynamic energy; White is down a pawn but possesses massive development.
5...Bf5 – The Gunderam Defense 5...Bf5: Black immediately activates the light-squared bishop, aiming to contest White's key invasion squares.
6.Ne5 – Commanding centralization 6.Ne5: the knight claims a dominant central outpost and clears the path for the aggressive g2-g4 pawn push.
6...e6 – Support with 6...e6: Black reinforces the center and prepares piece development, but overlooks White's impending pawn storm on the flank.
7.g4 – Hunting the bishop 7.g4! White thrusts the g-pawn forward aggressively, stripping escape squares from the bishop and winning key tempi.
7...Bg6 – Forced retreat 7...Bg6: the bishop has no viable alternatives and falls back to the only open square, stepping straight into a cage.
8.h4 – Decisive pawn thrust 8.h4! White directly threatens h5 to trap the g6-bishop permanently or tear open the entire black kingside.

How to exploit the position

White overwhelms Black's bishop with a ferocious kingside pawn storm

Plant the knight on e5 seizing a dominant central outpost and unleashing the g4 advance
Thrust g2-g4 forcefully driving the black bishop into an uncomfortable retreat to g6
Push h2-h4 immediately threatening to entomb the bishop completely with h5
Crack open decisive files on the kingside exploiting the tempi gained on the bishop

Master tips

Trapping the bishop on g6

After g4 and h4 Black's bishop on g6 has no escape squares and faces imminent capture