Shinkan (森閑,Shinkan, lit. "Silent Forest") is a command based off the Fuurinkazan to increase Yaya's endurance and sturdiness to intercept attacks. Yaya, in a relaxed stance, a stance to catch an approaching attack, waits for the opponent's attack to land. In the anime, whenever Raishin uses Shinkan on Yaya, he releases green strings of magic energy onto her, enveloping her whole body, glowing off with green magic energy for a short duration of time.
Unbreakable Machine-Doll Encyclopaedia