The Zanshin of a Zen Master

Sword Master Yamaoka Tesshu studied Zen under several Masters. The last barrier he had to pass was the "flashing swords" koan given him by Tekisui, abbot of Tenryuji in Kyoto. 

Tekisui was a no-nonsense, hardheaded type of Zen Master required for a strong willed Sword expert such as Tesshu. 

He also was an accomplished martial artist even though he never held a sword in his hands. During their formal encounters at Tesshu's home, the building shook with the sounds of Tekisui's tools :  shouts, iron fists, a heavy stick, pushing Tesshu on the Zen way.

Tesshu's close and senior disciple Murakami Masatada resented Tekisui's rude treatment of his master—after all, Tesshu was a personal adviser to the Emperor himself. And so Murakami secretly vowed to dispose of the arrogant monk. 

One night he followed him, intending to assassinate him.

Unfortunately, whenever Murakami was about to make a move, the Zen Master would suddenly glance over his shoulder, change direction, or disappear in one of the temples along the way. Murakami tried again the next two nights but never could get anywhere close to the very aware Zen master.

When finally Murakami gave up and confessed his plot to Tesshu. Tesshu laughed: "You immature fool! Even with a dozen of accomplices, you'd never be able to get near that Master."

Murakami began Zen training under Tekisui.