... Why?

zgryphon said:

... Why?

It's a Chinese saying synonymous to digging yourself into a hole..

zaregoto said:

It's a Chinese saying synonymous to digging yourself into a hole..

Some other sites suggest the idiom is similar to hoist with one's own petard.

NWF_Renim said:

Some other sites suggest the idiom is similar to hoist with one's own petard.

I guess that one's definitely closer with how detailed it is.

Amusingly, it seems the idiom from Hamlet is a double entendre. Both the obvious "blown up with one's own bomb" and apparently could be understood by people of the time as "blown away by one's own fart."

NWF_Renim said:

Some other sites suggest the idiom is similar to hoist with one's own petard.

Aha. (See also: shooting oneself in the foot.)