Iwasaki and Jnats (part 3)

Continued from Iwasaki and Jnats (part 2).

When I asked Iwasaki san and Mizuochi san how they sharpen their razors Iwasaki san asked me what I think of edge profiles.
He made forms with his hands like this:

Iwasaki san made a form like this (This is not Iwasaki san's hand)

"You can form a edge like this. It is a straight edge."

Iwasaki san made form like this too (hamaguriba).

"The edge can be like this (hamaguriba) too."
 "I observed beard hair cut with both edges and found that the straight edge makes a straight cut and the hamaguriba edge makes a diagonal cut."
I said "So the straight edge is better."

"The answer is not so easy." replied Iwasaki san "It depends on skin and hardness of the beard hair."
"If the skin is hard and beard hair soft a straight edge is good. If the skin is soft and hair is hard a hamaguriba edge is better." "Japanese in general have a harder skin so our razors have straight edge, But we advice barbers who have many western customers to sharpen their razors hamaguriba or if straight edge more wider angle."
"The angle of the edge is very important so if you have a razor for yourself you must find out which angle is best for you."

To be continued ....