Have you been practising a martial art for more than 3 years? Have you obtained your first Dan or higher? Are you proficient with a variety of Oriental weapons and can use a chopstick to kill someone? CAN YOU GET ACROSS A ROOM FULL OF FLOUR WITHOUT LEAVING FOOTPRINTS?
If you answered "yes" to all of these questions, YOU MAY BE A NINJA!
HOWEVER.
If you find yourself glowing with pride because you caught something that you dropped, you are not a ninja. Ninjas do not drop things by accident.
when you enter a room you auto-check the floor for pressure pads.or when you look at,say,the eifle tower and think,"i could climb that in winter without any tools.