In 'Bansenshukai', a book on ninja skills written in Iga in 1676, as well as 10 articles on the spy's mental skills, the points below are noted on the subject of practical skills. ・A ninja must not reveal his status as a spy to anybody . ・Important information must never be written in documents, only relayed by word of mouth. ・Occasions such as the night of a wedding celebration, the evening following a day of building work/physical labour or the day following an accident - such as a fire - in the neighbourhood present good chances to steal in and make a raid. ・When making a stealth raid, a ninja's escape route must be prepared in advance. ・Even if it means abandoning one's associates, a ninja must not get sidetracked when on a mission. ・A ninja must never let down his guard, even if the mission is coming to an end. ・A ninja makes use of ANYTHING that can be used.
