Aogami Super

[Hz_zzzzzz]

Impossible to really know. TF doesn't test every knife, and I'd be surprised if any hardness testing has been done for many years, if at all. For them its all done by eye and experience, which undoubtedly leads to quite a bit of variation. Not a lot of scientifically controlled processes unlike some Western makers eg Trey with his thermocoupled, computer controlled system.

Sukenari used to do they're AS that high. They had chipping issues, so backed down the HRC a little. I'd guess lower than 67-68, but higher than 62-64... but, just a guess.

From TF’s official website, they temper at 180C for 45 minutes. Based on the Hitachi heat treat manual, that’s corresponding to an HRC 64 to 65.

 

[Hz_zzzzzz]

Shiro Kamo is awesome! If you can find a Moritaka AS Knife under $200, they have one of the best heat treats. They also make their own material and use low temp warikomi to minimize carbon transfer from the core steel to the cladding. lt's a difference you can feel when sharpening a Doi, Moritaka, or TF.

I got my 270 Moritaka AS gyuto from them directly for only 20,550 JPY including shipping. It was less than $190 at the time last year and only $153 with the current exchange rate. I installed a $60 KnS handle on it and still below $250 all costs combined. Truly good value.

 

[Troopah_Knives]

l can’t possibly know, but from what you say it sounds like denka had thinner geometry than takeda, since it is generally agreed that takes a AS is not heat treated as hard as denkas. Of course with your particular examples this might not be true.

Could also be in the HT. I doubt it, but it's possible they avoid some or all plate martensite by doing a temper anneal or other pre-quench treatments.

 

[chefwp]

I only have one AS J knife in my small collection. It is a nakiri from Shiro Kamo's Shinko Seilan series. Love the way it cuts and sharpens.

I used to have one of those too. The edge retention was amazing, super value for the $$.