why talking about washitas is confusing
David Weaver
I'm going to show two pictures from the washita - both were done on the same iron.
The first is the one provided earlier, when digging in. The objective in that case is to remove wear and prepare for the buffer, the wire edge remains at the edge.
The second picture is from the same stone on the same iron ( I do not abrade oilstones unless bevel cutting on razors, so neither of these is done "with a slurry", and I don't mix a designated razor bevel stone with other uses ). After digging in like the first picture, the follow-up is 10 seconds of light work on the back of the iron. The opposite side is prepared with plane uni method 1 (bevel side only) as I'm planing junk wood with knots and it comes into its own there.
These are the kinds of things that make it hard to answer questions about natural stones. Right now, I probably have 7 or 8 washitas, I don't have more than one of them because the extras serve any function, rather that they reward curiosity as a side hobby. Some are sort of like each other and others are much different. If one gets 50 and tries to separate them by some standard, you end up with three or four groups of stones, but then the characteristics of the finish of each is slightly different yet. Familiarity with a good one is more important than having an array.
The nature of the abrasive in these stones is softer than a hardness test would indicate the steel to be on most japanese chisels. The stone still cuts the chisel, it just cuts it finely. I have no idea exactly why technically, just what is. For someone skilled and with plainer steels, the feel of anything close to 62 hardness (-5 to perhaps +3) can be judged really well by these stones, and the system can be gamed to use the same stone to do different things on different tools, or even different things on the same tools. A $50 washita will match the finest of japanese suita stones I've come across (which is many). This is offputting for some, especially if they get their information from dealers or gurus. It can also do semi finish work well. If most people sharpening japanese tools were on the clock, they would probably use a soft arkansas or a washita stone that had been abraded after a 1k stone and then go directly to their finest finish stone. You can demonstrate something like that, but you can't make a dent to someone who has already determined that something different can't possibly be better.
We don't consider the effect of hardness and pressure on stones that much because we don't necessarily have to. It can be useful, but it's hard to communicate. Where this really becomes useful is in setting up razors, but even with folks who claim to know a lot about honing razors, the discussion falls flat because there are folks who get paid to hone and they get confused with what's correct and what's good for them to keep promoting after they've dug a trench in the past (as in, if someone has a menu of stones they want people to purchase and they have a method that they use day to day, that becomes the correct method. This sounds familiar with some woodworking gurus. You can find someone who failed at something and point at it as that. One of my favorite things that I've ever seen Warren say can be paraphrased to "don't confuse you can't do it with it can't be done". I'd go a measure further than that, which I've learned to tell myself - don't confuse things that you don't want to do with things that you can't do, because you're one step away from telling people they can't do things you don't want to do. Like simple solutions for clearance on bevel up planes.
All that said, while I find these things immensely interesting, I can't much argue that except or razors, the buffer has kind of obsoleted a lot of my exploration in this stuff. 
