Haganetsuki Genno Japanese Hand Made Hammer by Hiroki - 180 Monme

Additional Information: Unused. Brand new condition, made by the hammer blacksmith Hiroki Aida about 10 years ago with high production precision.

I asked the collector of the three Hiroki steel-laminated square gennou hammers listed on the website if he could find out when they were originally purchased. I received good news recently: it has been confirmed that they were purchased in June of Heisei 23 (2011). That means these three hammers were crafted by Hiroki 15 years ago. 

According to information provided by Tsuchida-san, Japanese genno (hammers) are traditionally classified into four size categories:

Mame-genno (豆玄翁): Refers to 20 to 30 monme (approx. 75–112.5 g). Used for driving nails and other small hardware.

Ko-genno (小玄翁): Refers to 50 to 80 monme (approx. 187.5–300 g). Used for striking oire-nomi (bench chisels).

Chu-genno (中玄翁): Refers to 100 to 120 monme (approx. 375–450 g). Used for versatile, general-purpose tasks.

Dai-genno (大玄翁): Refers to 150 monme or heavier (approx. 562.5 g and above). Used for striking heavy timber chisels (tataki-nomi / atsunomi).