Tsumego (Capture) #5309457 (2-move)
Black to play — capture the marked white stones
Capture these stones
Why this move works
The answer is E6 then G6. The three white stones (G7, F7, F6) have liberties at G6 and E6.
Play E6 first. Filling G6 first lets White escape to E6. Block the extension at E6, then fill G6 to capture.