look up any word, like ratchet:
 
1.
A cry to confuse security guards when tryiong to sneak into an unauthorized area.
"Japan four. The shamshee? Japan four!" Tom Green - Freddy Got Fingered
by Brandon March 11, 2004
 
2.
"Japanfour" an invisible something on the ground, that kind of has the meaning that your stepping in something bad. Or that theres something bad on the ground infront of someone.
"OMG right there, JAPANFOUR! Dont step on it"
"You see that japanfour right there, oi, oi you japanfour, you see the japanfour"
by DenV May 14, 2007