1.
last moment, eleventh hour, last-ditch situation
The very last possible moment before a deadline or decisive point. Often implies being pressed for time or backed into a corner.
Etymology
Historically, 土壇場 referred to the execution ground — a raised mound of earth (土壇) where beheadings took place. From this, it came to mean a situation of final desperation with no escape.
Usage
Very commonly used in everyday Japanese to describe last-minute situations. Frequently appears as 土壇場で (at the last moment) or 土壇場になって (when it came down to the wire).