The conditions to perform a Fatal Flash vary slightly in each Samurai Shodown game, as well its harmful effects, but usually the rule is having a temporary Gauge active, such the Explosion or Meditation Gauge. The effects of the attack are stronger when the Life Gauge is more depleted.
- Samurai Shodown IV - command: Medium Slash + Strong Slash + Kick. Can be performed only when the Explosion Gauge is active. The damage inflicted is inversely proportional to how much Life the player's character has; being near KO will result in critical damage while a Life Gauge that is 50% full or more will result in minimal damage.
- Samurai Shodown 64 / Warriors Rage - command: Strong Slash + Kick + Special buttons at the same time. Same conditions as Samurai Shodown IV.
- Samurai Shodown: Warriors Rage - command: pushing any 3 buttons out of Light Slash, Strong Slash, Kick, or Dodge simultaneously. Same conditions as Samurai Shodown IV.
- Samurai Shodown V / Special - command: Medium Slash + Kick + Special buttons at the same time. Can only be performed when the Meditation Gauge is active. The damage inflicted is proportional to how full the Sword Gauge is, and inversely proportional to how much Life the fighter has (less Life means more damage).