Komei Tadahiro saku 古銘忠廣作 signed Wakizashi, Homarekizu 誉傷 Raijin 雷神 Kozuka, Edo period

There is a Homarekizu(誉傷) on the Mune side of the blade.
This appears to be a cut mark sustained during combat when the blade was used to defend against an opponent's sword attack.

Signature : Komei Tadayoshi saku
Nagasa : 445mm (17.52 in.) 
Sori : 10mm (0.39 in.) 
Total length : 645mm (25.39 in.) 
Motohaba : 26.9mm (1.06 in.) 
Sakihaba : 18.5mm (0.73 in.) 
Motokasane : 6.4mm (0.25 in.) 
Sakikasane : 4.8mm (0.19 in.) 
Blade Weight : 431g
Total Weight : 824g