The Slash Rune is a special support rune found in Suikoden IV. It can be found as a rare find in an item shop.
If the character with this rune attached is in the party, when weak enemies appear, "Retreat" becomes "Flashes". When the command is chosen, the screen is cut in two and instantly kills all enemies.
This rune can be useful for leveling up certain characters and clearing useless random encounters.