Tenha Seiou Zan

Tenha Seiouzan ("Heaven Supreme Vile Spark Slash") is one of Haohmaru's Super Special Moves, and one of his signature attacks in the Samurai Shodown series, first appearing in Samurai Shodown II.

Description
Haohmaru does a strong downward diagonal slash, creating a mass trail of energy in its wake. It is essentially a souped-up version of his Zantetsusen.

While originally a meter-costing move in most games, there exist some games such as the 64 games where Haohmaru has this along with a variation just called Seiouzan ("Vile Spark Slash") done as a followup to his Gouha series via his Bust version that Rasetsumaru does not retain.

Strategy
One of the best Weapon-Flipping Techniques in the series due to its fast startup, range and damage. It can be used as an on-reaction punish against most moves from almost anywhere on the screen, and can be used to hit the start up of slow moves like some fireballs.

Interestingly, in KOF XV, the version starts 8 frames slower than the  version.

Of course, this move tends to be rather committal and is easily punishable. But on the flipside, the CvS2 version especially has full invulnerability frames at the startup along with the usual hefty range. This often makes it a powerful one-shot punisher at poking range for any of the non-cinematic versions.