unknown japanese boobytrap

[kiwieod]

got this photo of a japanese boobytrap device,has anyone seen this before?
im not sure how it works,looks like you set it up on the base plate(square block with spanner on it)and bury it in the ground like the british N0.8 switch?
and maybe the small cylinder with the writng on it is the charge?
can someone translate the writing

 

[sgdbdr]

Looks like some kind of alarm mine to me.

 

[kiwieod]

yes the little tube with the writing on it could be some sort of flare,seems to be missing some sort of trigger device though