Cannon in, doors shut
In a smothered mate (闷杀) the checked king has no flight square because his OWN pieces stand on every exit. Here the advisors hold d9 and f9, and Black's own pawn on e8 even serves as the cannon's screen. One quiet slide of your cannon ends the game — find it: it fires through the e8 pawn, the king cannot step out, and no defender can reach the line to block.