Knives made from powder metallurgy steel are relatively new. The powder metallurgy HSS steel HAP40 manufactured by Hitachi can be hardened up to between 64 and 68 Rockwell. We chose 65-66 HRC. It is a fine grained steel that takes a very sharp edge. But of greater note is its almost supernatural ability to hold that edge. No other steel on the CKTG site gets even close to HAP40 in terms of edge retention. We have just started working with this remarkable steel and so far have been blown away by its strengths and abilities.
The fourth knife in the new line of HAP40 knives by Kohetsu is this great looking 240mm gyuto
. Its 50mm height places it about average compared to other 240mm gyutos, while its 2.5mm thick blade (at the heel) and 8.4oz weight are also typical for this type and style of knife. What’s not average is its performance, especially related to ease of edge maintenance. It has a nice progressive grind which Mr. Tsukahara grinds more on the right side than the left and he feathers and thins out the tip for nice cutting performance that will work well for left and right handed users. I shot a video of him sharpening these knives that you can view at the bottom of this page.
Please note, the knife sharpener intentionally thins the edges of these knives to make them perform better, especially on the tip area. Often times you will see a hazy/cloudy scratch pattern as a result. This is not a defect. He is doing you a favor by putting in extra work. Please look at the 4th photo on this page to see it.
If you seek a blade to keep on ticking after a shift-long licking then this outstanding kitchen knife just might be the answer to your needs. Finished with a mahogany Western style handle and stainless bolster, it looks good too! A CKTG exclusive.
Weight: 8.2 ounces
Blade Length: 240 mm
Thickness at Heel: 2.5 mm
Blade Height: 49.5 mm