Q&A with Iizuka san

Continued from Shigefusa's Workshop.

After the workshop tour I made some Q&A with Iizuka san.

My first question was about double bevel geometry.
I asked Iizuka san about razor gyuto and what he thinks about it.

The answer was:
"Razor gyuto and flexible slicer are made with steel only and do not have clad. All knives I make have clad. The clad is not elastic and if I make my knives thin like razor gyuto or flexible slicer they will bend."
He continued:
"I make knives with clad because it is far better to sharpen by hand and the hagane can be heat treated harder for sharper edge and better durability."
"Many chefs like the stiff feeling of the knife and the spine is tapered so you can do small work with the tip part too. I think the distal taper spine is more versatile."

I asked about what he thinks of honyaki.
"The biggest concern for clad knife was the bending after years because of different stress of jigane and hagane for single bevel knife. Honyaki solves this but it has also many inferior characteristics. One is difficult to sharpen. Other is the failure rate at heat treatment if you want the steel hard. I solved the problem making kitaeji clad. Kitaeji is a mixture of layers of carbon steel and very soft steel. Because it contain carbon steel the stress is lower and does  not bend after years. It is also very easy to sharpen because it has very soft steel."

After that answer I said that your kasumi single  bevel knives has reputation too not to bend after years.

Iizuka san smiled and said that he take care of heat treatment for kasumi knife too that they do not bend after years but he said kitaeji are better.

I asked how many times he bend the carbon steel and very soft steel laminate to make the layers.

The answer was five or six times. If bend less it will be uneven and if you bend to much you do not have the patterns. So the kitaeji has 32 to 64 layers.

The steel of Shigefusa knives are hard that you can scratch soda lime glass (I think it is 63 to 64 HRC) .
I asked whether such hardness is needed for thick knife like Deba and what he thinks of chipping.

The answer was:
" Many professionals who cut fish like the sharpness and durability of my Deba. It may chip against hard fish bones but you can still cut after that. If the Deba get dull you cannot cut a fish anymore. These professionals want to finish a shift with only 1 knife."

I asked Iizuka san why he does not make razors? (He has learned from Iwasaki Konosuke)
The  answer was:
"Iwasaki san is better in making razors so i do not make it. To make razors is very difficult. You will hurt if you do not make it correct an customers will say "ouch".
I make kitchen knives for fish and fish does not say "ouch"". And he smiled.

He showed me some staff which are in this room an I made some pictures.

360mm Yanagi

Most long  Yanagi are 300mm or 330mm. 360mm are not so common.

360mm Yanagi and a Petite with western handle

Note that the western handle bolster is free forged from the same steel bar
as the blade. Very few blacksmith do this type of bolster.

Shirakata san's 1000year nail

I found this nail and  asked if it is  the famous 1000 year nail by Shirakata san which story is in Japanese school book.
Yes it was an Iizuka san is friends with him.
You can read it here with English translation (PDF):
1000 year nail

I got great hospitality at Shigefusa workshop and thanked Iizuka san and his family because it was time to leave.

The last picture is how Iizuka san and family send off in front of his house.