Answer raids with geometry
Black's chariot has crossed the river and squats on g2, eyeing your e2 chariot. The instinct is to chase it — the correct answer is geometry: the cannon slides to e1, where it defends nothing and everything. It sits behind your chariot on the same file, so the moment Black's raider is captured, the cannon's sight-line extends all the way to the black king. The counter-capture is therefore also a check — and the raider's accomplice must abandon the post to block it.