When I hunt Isshin lists in my meta, I think about the deck’s two weak points: reliance on attacking and a tendency to overextend. So I pack answers that punish attacks and answer many bodies at once. Instant-speed single-target exile and targeted removal — think 'Swords to Plowshares', 'Path to Exile', 'Anguished Unmaking', 'Assassin's Trophy' — are excellent because they can strip a commander or a keystone creature right before combat. That denies triggers and often collapses their tempo.
Beyond spot removal, mass removal is critical. 'Toxic Deluge' is a personal favorite because it scales to the board without resurrecting tokens, and 'Cyclonic Rift' (overloaded) wipes nonland permanents for a big tempo swing.
Artifact- and enchantment-specific answers like 'Vandalblast', 'Return to Dust', or 'Krosan Grip' help when Isshin decks lean on equipment or
Anthem enchantments. Also, soft-lock elements — 'Ghostly Prison', 'Propaganda', or planeswalker-based taxes — make them pay dearly for swinging. If I can combine
graveyard hate when relevant ('Rest in Peace') and early removal, Isshin’s momentum stalls fast, and I close from there. I keep my plays tight and avoid letting them go wide for free.