15 Minutes S2021E12 - NINJA TRUTH Episode 15: Ninja Communication

Since ninja were engaged in espionage, they had to gather information and accurately convey it without anyone knowing. Typical means of information transmission included smoke signals, a cipher using knots in a rope, and special methods of transporting secret messages. But in the second half of the episode, we'll look at their ultimate method of concealing information: invisible ink! Find out how they did this, and follow Chris as he makes his own secret message with ninja techniques.