Removing the defender
Take the piece that guards something, then take what it guarded.
Example
The rook attacks the bishop on d4, but the knight defends it.
- 1. Bxc6+: Remove the defender first (with check, too).
- 1... bxc6: Black takes back…
- 2. Rxd4: …and the bishop on d4 has nobody guarding it.
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