Quiet moves, loud finish
An attack is mostly quiet moves. Watch this model game: Red develops a cannon to the central file, walks a chariot to the f-file, brings the second chariot over — four moves in which nothing is captured and nothing is threatened out loud. Yet every move adds one more attacker to the palace's doorstep. The moment the f9 advisor is captured with check, the position is already forced: one king step, and the c5 horse lands on e6 as the cannon's screen. Mate. Your task is the conversion: find the capture that starts the forced finish.