I was the original owner of this knife and owned this knife for over a year. Most of the comments here are speculation based on other of Mario's earlier knives, and they're not consistent with my experience.
This knife was a very good performer overall; although it's not a laser, it cut very well in many types of cuts, especially push cutting toward the heel. Fast or slow, it performed very well.
Initially, I actually found pull cutting to be the worst, especially toward the tip, and horizontal cutting through the tip because of the profile of the edge along the tip as it was essentially flat and almost bird's beaked. But, I reshaped the tip so that it had a slight curve and it performed much better. Nonetheless, that's relatively speaking - the knife performed well all around; the best performance quality of this knife was the food release.
When I sold it, it needed just a little thinning - the knife was sharpened only about 5 times by me, Jon and, IIRC, tk59. The CPM154 is hard; it loses its freshly sharpened feel very quickly, but keeps 80-90% of its sharpness for a long time.
Here are my original comments to Mario in February 2012 after I used this knife for a bit and gave this knife its first big workout:
I'll start off with my criticisms since they're few. I go back and forth on the tip. Sometimes it works great, other times it's a little troublesome. It seems like you really have to work to get the right angle, or right follow through with the point on the board to make sure you cut through everything with the tip. I think it needs to be rounded just a touch - and I mean "just a touch" so that it's not flat, but just very slightly rounded. I think the natural draw through motion of using the tip will allow a person to get full use of the entire length of the tip when you do this. I noticed when I was going through onions, I had to make sure I made full contact with the board with the tip to ensure that I went through the entire onion. Second, and I haven't had any knife really do great on carrots, but the knife seems to have some steering and wedging issues with hard carrots. That, to me, is the holy grail of tests. I haven't owned or tried a knife yet that goes through carrots very well.
On to the positives. I think the geometry is very good. In fact, as I chopped onions, doing horizontal slices and then vertical slices, I noticed how easily it went through the onions. It was a breeze to get through six onions quickly. Celery and bell peppers were easy to cut. I cut the bell peppers skin side down and did a small chop quickly and efficiently. Onions stuck the most to the knife, but I think that was a product of the onions being very moist. Other than that, I got through the vegetables extremely quickly. Also, I've been fooling around with various grips on the knife and it's become easier and easier to use. I don't think the handle is too large now. I'm also really enjoying that amboyna wood. That is a winner.
With respect to chicken, this is where the tip seemed to really do its best work. Because it's almost a straight point, when boning the chicken, it was very easy to cut - the knife cut where you put it. A finer edge would have made the cutting easier, although possibly sacrificing feel, but it still did a great job.
I think the one thing that most surprises me about the knife everytime I use it is how easy it is to use. The balance is extremely good, and for an over 240 mm blade, it doesn't feel that big, even though it's more substantial than other knives I've used.
I'm not sure how to improve the grind, but I think that, and the edge along the tip, are the only things that need to be worked on performance wise. But, I think going forward, the changes you may want to make are minor. It's a very good performing knife - better than other knives that are more expensive in my opinion. I did notice that my knife came with a few scratches on it. But this, again, is minor. The edge also seems to be holding up well.
My comments of cutting above were based mostly on push and slight rock chopping, and some pull cutting.
I also want to clarify a few things. This knife isn't in the condition that Mario made it/that I purchased it, or the condition that I sold it, and, based on the comments of the current owner, it's likely not performing the way it was when I had it. Based on the scratches on blade face of the knife, and the comments about performance, the geometry of the knife has very likely been changed. I want that to be clear so that there are no assumptions that this knife currently is how Mario's knives are.
In my experience, thinning, per se, doesn't necessarily improve performance; proper thinning does. Also, proper edge shape makes a big difference in how a knife performs, especially in how a knife feels when it first goes into food.
Also, the handle was oiled by someone besides Mario or me -- natural amboyna doesn't need to be oiled -- to be clear that Mario did not sell the handle that way.
And, now that I've used a lot more knives, I can say that when I had it, it performed much better than a Masamoto KS (I've owned one and would choose this knife over a KS any day of the week as it was a better cutter than the KS I owned), but may not cut as well as a Kono HD, but will have MUCH better food release.
"Don't you know who he is?"
The KS is highly overrated IMO, I just used that (and the other knives) as examples that many on this forum are familiar with. No offense to anyone who's a fan of the KS just not my cuppa. Neither was the ITK, so that makes me an outcast I guess...
The AI does not love you, nor does it hate you, but you are made out of atoms it might find useful for something else. - Eliezer Yudkowsky
I resharpened it at a higher angle and set a bit more of a bevel in the knife and it performs alot better than before I agree with the comments above about how it performs. The food release is amazing you notice it more when you switch back to other knives. Ill add more information when I used it at work as using a knife at home for me isnt a good enough test. I dont push myself at home because time isnt a factor. Thanks for the constructive critisicm. Just to recap after I put a more aggressive angle on the edge it cuts alot better it enters food better. All my other gyutos are more laseresque so I put a very steep edge and I find it best.
all these pictures are before I sharpened it and after I polished all scratch marks out of the blade and took the true oil off.
Mhlee - fantastic post, thanks for sharing.
Our differing reactions for how to incorporate this geometry and profile into our own cutting styles seems the epitome of 'different strokes for different folks'. I mean this in the best possible way.
I certainly agree with that.I think the geometry is very good.
Jai - It seems clear that you know what you are doing. Both for maintaining and using a nice knife. I would be very interested to hear an update after you have spent more time with the knife. It really looks great.
If you're going through hell, keep going.
i find that with a fat spine knife, thinning is an on going thing. i thin my kochi every sharpening session. when you think you've thinned enough, you're just going to find out that you need to keep thinning a week later. so the geometry changes every single time, which is cool and strange at the same time, haha. some weeks i love it, other weeks i'm like what da??
sometimes i'll thin very high up, other times only half an inch up from the edge and anywhere in between. it leads to changes in convexity as well.
Ok guys so after thinning it twice it cuts like a dream it finally took a great edge after the second thinning and still cuts well with no stiction. Really enjoying this knife and happy with the grind. I honestly just think it had a tad to much steel behind the edge so it was causing it it wedge and do horrid stuff. Thanks for all the helpful advice and information. Im sure this knife has been sharpend alot so it was most likely just the case.