For Special purposes, Kawari-Zukuri 変わり造, Rare style Oozori TANTO, Edo period

This Tanto has an unusual style and appears to have been custom-made.
Despite being a Tanto, what purpose did it have to be used to have such a large curved blade?
Furthermore, the blade is very thick, and the Jigane is interesting and varied.
It is clear that it was made with great care.
It appears to have had a special purpose.

Signature : Mumei (Unsigned)
Nagasa : 246mm (9.69 in.) 
Sori : 7mm (0.28 in.) 
Total length : 400mm (15.75 in.) 
Motohaba : 28.8mm (1.13 in.) 
Sakihaba : 19mm (0.75 in.) 
Motokasane : 7.8mm (0.31 in.) 
Sakikasane : 5mm (0.20 in.) 
Blade Weight : 286g
Total Weight : 452g