In the Advance Variation, 1.e4 e6 2.d4 d5 3.e5, White grabs space with the pawn on e5 and Black attacks the base of the chain at once with 3...c5. After 4.c3 Nc6 5.Nf3 Qb6 the whole fight is about d4: Black piles up on it with knights, queen and the ...cxd4 exchange, and White defends it with c3, Nf3 and the bishops.
That pressure explains the most common white mistake in our data. After 4.c3 Qb6 5.Nf3 Nc6 6.Bd3 cxd4 7.cxd4 Bd7 White develops with 8.Be3?, and the queen takes on b2. With the queen on b6, b2 is always the first thing to check before moving the c1 bishop.
Black's typical mistakes are the opposite: grabbing d4 when it is not really weak. After 4.c3 Nc6 5.Nf3 Nge7 6.Be2 Black plays 6...Nxd4?, but 7.cxd4 and the knight is simply gone, because the queen is not yet on b6 to recapture. The same happens after 5...Bd7 6.Be2 f6 7.O-O Nxd4? 8.cxd4. Count the attackers and defenders of d4 first: the trick only works when the queen already backs up the knight.
The pawn on e5 creates its own tactics. After 5...a6 6.a3 the natural 6...Nf6?? puts the knight on a square the pawn controls, and 7.exf6 wins it. In a different move order, 5.Be3 Bd7 6.a3 Qb6, the capture 7.dxc5? opens b2 again and loses a pawn to 7...Qxb2.
The puzzles below come from these exact positions, for White and for Black, and most of them are about counting: how many pieces attack d4, b2 and f6, and how many defend them.
| Mistake | Side | Count | Avg loss |
|---|---|---|---|
| 8...Be3 | Black | 39 | 3.9 pawns |
| 6.Nxd4 | White | 34 | 5.3 pawns |
| 7.Nxd4 | White | 30 | 5.4 pawns |
| 6.Nf6 | White | 29 | 5.1 pawns |
| 7...dxc5 | Black | 25 | 2.9 pawns |