How to defend from the crazy knight attack opening at Nf3 ..., Nd4 in Atomic chess?

Question

Here's a game of Atomic chess I played with a friend. As you may see, neither of us are very good at Atomic chess and the game ended in under twenty moves.

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[Event "Casual game"]
[Site "http://lichess.org/I9pp1BLC"]
[Date "2015.06.17"]
[White "sethdj"]
[Black "Unihedron"]
[Result "0-1"]
[WhiteElo "1368"]
[BlackElo "1632"]
[PlyCount "32"]
[Variant "Atomic"]
[Annotator "lichess.org"]

1. Nf3 f6 2. Nd4 e6 3. e3 g6 4. Bc4 d5 5. Bb5+ c6 6. Qg4 Na6 7. c3 Nc5 8. Bxc6 {C6 capture removes itself and C5 knight.} Qb6 9. Qxe6 {E6 capture removes the queen herself.} Qa6! {Mate threat at Qf2# / Qg1#.} 10. Ne6! {Nuke threat at Nxf8#.} Bxe6 {E6 capture removes the bishop.} 11. d3 Qa4! {Mate threat at Qd1#.} 12. b3 Qg4! {Mate threat at Qd1#.} 13. f3 Qh4+ {Checkmate is now inevitable.} 14. g3 Qh3 15. Kd1 Qg2 16. Ke1 Qe2# { White is checkmated } 0-1

But that's not really the point here. The opening of 1. Nf3 f6 2. Nd4 is a very tricky knight attack, and when playing against a tricky player they may respond with Nb5 or Nf5 after e6 and c6 respectively, where e6 and c6 aims to protect those two grids. What is a good response here?

Answer 1

Black, who defends, should move its Knight to h6. There it protects f5 so if white moves its knight there, black can capture it. Additionally, if white does Kb5 with the intention to attack Black's Queen (and potentially king, if black attempts to defend the queen), Black can go forward (Ng4) and then Black wins: Black can either capture a pawn next to the king, or the queen if White moves this pawn, and white can capture the queen with some other pieces when black does Ng4, but black's king is still safe.

[FEN ""]
[White "White"]
[Black "Black"]
[Variant "Atomic"]

1. Nf3 f6 2. Nd4 Nh6 3. Nb5 Ng4 (3. Nf5 Nxf5) 4. f3 Nf2 5. Nxc7 Nxd1# 0-1

It can happen that white does h3 after Nh6 to block a potential Ng4 from black, and then black has to move a pawn to protect his pieces if white would move Nb5:

[FEN ""]
[White "White"]
[Black "Black"]
[Variant "Atomic"]

1. Nf3 f6 2. Nd4 Nh6 3. h3 c6

Answer 2

2... c6 Should be played. You shouldn't let your opponent play 3. Nb5 safely unless you're welcome of losing your queen. Here's the line that shows the guaranteed queen casualty:

[FEN ""]
[White "Attacker"]
[Black "Defender"]
[Variant "Atomic"]

1. Nf3 f6 2. Nd4 e6 3. Nb5 (2... c6 3. Nf5! {Nuke threat at Nxe7#.} e6~ {Or e5, there's no real difference.}) Bb4! {Nuke threat at Bxd2#.} (3... Qe7~ {A way to reduce material loss. As the queen is guaranteed to be lost, this move saves the minor pieces. Unless your opponent decides to remove them with Nxc7 anyway and let your queen live, which is questionable.} 4. Nd6+ Qxd6 {This capture removes the queen herself from the explosion. The pawn can be used instead, but it wastes a pawn.}) 4. c3 Bc5! {Nuke threat at Bxf2#. The threat is kind of redundant but the idea here is to live longer.} 5. e3 c6~ {The idea here is to save a pawn.} 6.Nc7+ Qxc7 {C3 capture removes the queen herself, as well as the light bishop and B8 knight. The only possible move, as Ke5 / Ke6 leads to checkmate, and Kf8 is simply an inevitable checkmate. See additional line.} (6... Kf8 7. Ne8! {Either of Nxf6# or Nxg7# wins for white with a king explosion. Also, Qxe8 is illegal because the king would blow up.})

For the 2... c6 (2... c5) 3. Nf5 e6 line, on Nd6+ you can capture the knight with your dark bishop, and on Ne7 you can save your queen and launch an attack with Qa5 threatening Qxd2#, and then force the d-e-f pawns to be moved, which makes it harder for your opponent to launch an attack with a stuck diagonals department. Therefore the knight wouldn't be able to create much of an impact and may finish off with an explosion at 4. Nxg7 that removes the rook (and two minor pieces), but with a queen ready to set off in a diagonal, you can try for a surprise attack and build defenses.