Ittōsesshō

is a Kendō technique meant to cut the enemy's Zanpakutō completely in two.

Description
By first finding a weak point in the target's sword, usually a Zanpakutō, then flooding the users own sword with dense spiritual pressure, one clean cut is made with the Zanpakutō, completely cutting the target's own Zanpakutō in two. It is created based on the first tenet of Kendō.

If the Zanpakutō in question is in Bankai, the damage is permanent.

Trivia

 * Unlike some of the other Kendō techniques, this technique is not based on a real-life technique, rather, it is based on one of Kendō's tenets.