Explanation

Sometimes you can capture an opponent's piece, but capturing it comes with a disadvantage, for example if your opponent has other threats, or if the piece which can make the capture is currently pinned. An intermediate move is a move that you play instead, which changes the situation so that you can make the capture later without that disadvantage.

In these levels we are looking at intermediate moves to avoid checkmates.

Examples

White has just captured a pawn on h4 with the bishop, relying on 1.Qxh4? Qg5#. However, the move was a mistake, because White can win with the intermediate move 1.f3!, preventing checkmate and attacking the queen at the same time. Note that the queen has no retreating square where it can protect the bishop on h4. Hence, after White retreats with the queen, for example 1...Qg6, White can capture the bishop with 2.Qxh4 and has a winning material advantage.

Black could win a piece with 1...fxe3, however that would come at a high price, because 2.Qxf7# would be checkmate. Instead, Black can win with the intermediate move 1...Nb6!, attacking the unprotected bishop on c4, and opening the line from c7 to f7, so Black's queen is now protecting f7.
Now Black is attacking two pieces, and White will lose one of them, for example 2.Bb3 fxe3.

Sometimes the intermediate move can be a sacrifice, for example:

Let's count the material first: White has a bishop and a knight for a rook and three pawns, so is an equivalent of two pawns down. Black is also attacking the bishop on c3 with the rook on c5. White could capture the rook with 1.Bxh8, however then 1...Rc1# would be backrank mate. Instead, White can win with the intermediate move 1.Ne4!, which is a fantastic multi-purpose move:

• The knight protects the bishop on c3, which was under attack.
• The knight attacks the rook on c5.
• The knight makes an escape square for the king.
• The move is also a sacrifice.

Because both rooks are under attack, Black is forced to accept the sacrifice with 1...dxe4, but now White can capture the rook with 2.Bxh8, and 2...Rc1+ would no longer be mate. Having won back an exchange, White now has a bishop for three pawns, and has restored material balance.
Note that Black could also have accepted the sacrifice with 1...Rxc3 2.Nxc3, with a similar result.

Visualization

When you can capture an opponent's piece, don't just grab it. Make sure that your opponent doesn't have any threats. Those threats can exist before your move, or only after your move. If such threats exist, consider an intermediate move or check.

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