I have this one from this place. People inexplicably laugh when they hear the translation!
www.takase.com
Cry in the dojo - Laugh on the battlefield (dōjō de naki, senjō de warau)
道場で泣き戦場で笑う (dōjō de naki, senjō de warau): weep in the dojo, laugh on the battlefield. A maxim of training, hand-brushed on a scroll by Master Eri Takase.