Official Webpage of A.Tanzadeh, 8th Dan, Kyoshi 糸東会

Sen no Sen, 先の先 (To anticipate an attack)

To anticipate an attack and to take the initiative.

“Sen no Sen” is that you know what your opponent is going to do so you will strike before your opponent moves.

Sen means “before”. It is also a shortened form of sen-te (literally “beforehand”) and typically refers to “an attack” in Karate and Budo terms.