Something was wrong with the saw. 90% of gyochuko and Z saws do exactly what they're supposed to do, but some will shed teeth on oak, so you have to watch what you're doing and what you're doing it again once you get a replacement blade.
I've not found the mid grade of saws any better (z and gyochuko sell new blades in japan for about $5 - $11. We get smacked by retailers on replacements in the states and in europe) - those saws are machine made or partially machine made and just don't seem to perform better, but I think retailers (woodcraft here in the states) that tend to have higher prices try to sell them as differentiating. Once in a while, there's something (like a rip only dozuki) that comes up and may be better for a specific task, but as pleasant as they are to use, they don't save time and they cost 4 times as much as a general dozuki.
At any rate, if you get all the way up into custom saws, you can get anything you want, including a rip kataba in a large heavy size like a western saw that will feel like you can't break it ripping.
Years ago, on sawmillcreek, I had gone from japanese to western saws as I started to work entirely by hand. There's nothing sold here (despite some japanophiles' wishes -they rip one cut with a ryoba and then declare it equal) to a disston rip saw if you're actually working by hand, and that's a big problem. So, stan covington picked up on it (i'd spent a lot of money on the coarsest of disposable saws by then and they just weren't up to it), and he went to a smith that he knows who makes 20 saws per year more or less and took the guy some western saws (including a rip d-12 disston). The sawmaker was impressed with the taper quality and accuracy of the disston and he made a pair of katabas - keep in mind, this guy makes these by hand - you can get whatever you want.
Stan sent one to me. I took a video of it, but I was in my pajamas and I'm fairly sure I've deleted it by now. I found it harder to use than a disston saw, but professional sawyers in japan found it easier than a disston saw (not surprising), and we had opposite experiences with speed. However, if one was used to pull saws, it would've been the solution for long ripping.
The trouble was, even though it was made by a reasonable maker, it was $750 at the time for each one. I was thankful to try it. There are some things necessary when you're pulling a saw to make it cut equivalently in effort to a western saw - more tooth hook, etc, but tooth count and firmness of the custom saw was a lot like a disston.
I can cut 75 linear feet of 4/4 - 8/4 material in a given day with disston saws and not feel anything other than a little tired (planing of the wood goes along with that to make door sticking, etc), but I was played out by the japanese saw in one cut because it's a different set of muscles. It could be equal.
I think beginners and people who don't do much work by hand will like the decent pull saws for joinery, I've moved to western saws and rarely use them - across the board. The thing about the japanese saws that's attractive to beginners is that on joinery, you can practically lay the saw on a spot, pull it, and it will cut where you put it. ham handing starting is less. No sharpening, which people don't like, I guess. But there remains no good solution for productive ripping of western wood without engaging a custom saw maker.
I've bought another kataba or two old and used off of japan yahoo auctions, but none is close to the equal of the saws that stan had made. What kept me from spending the $750 is pretty simple. I could see getting as good with it as I am with some of my western saws, but they were about $50 on average. It just wasn't justifiable even though it was unique and neat. Nobody on here would've been able to physically break the custom saw, either - it was tempered to good toughness (not glass hard) and the spine and tang were very heavy. But it came out a whole lot like a western saw (not surprisingly) when a capable and intelligent custom maker was given samples of wood that it was to cut.
