Thread: Kamijo Yukio, revealing the secrets of steel

So after the Kamijo colaboration iwasaki started to quench the blades horizontaly similar to katana ...


...also the Tamahagane recipe or heat treatment changed after ending the colaboraton with Kamijo.

The tamahagane made in colaboration with Kamijo is something you have to test to understand....it is a bit softer then later iwasaki tamahagane...but honing is child's play and it takes a sublime edge so easily.

After Kamijo colab ended Iwasaki wanted harder Tamahagane so he altered the heat treatment and possibly the recipe too. Resulting steel was indeed harde and fine grained but some excepionaly hard blades 64-67 HRC were difficult to sharpen and prone to chipping.
Also the shaves they provide are not that impressive....or maybe i did not manage to get the best out of them...who knows...i like the old tamahagane better even if it is slightly softer. @ 62-63 hrc(tested).

After Kamijo retired Iwasaki started colaborating with master Tanifuji Fukutaro who took over finishing and scaling the razors forom Kamijo.

This is the generation that Tamahagane razors got progresively harder...and all western ground razors were horizontaly quenched.
I was lucky enough to have a few of the razors from this time period:


A iwasaki Tamhagane and an Iwasaki no. 90 from this period.

Also an Iwasaki Wedge from that period...these are a bit rare because from my understanding...during Kamijo colaboration wedge grinds were more frequent then in the Tanifuji colab period when they became less and less manufactured.