Craftsmanship in Wood

In the Tréteau build(**) on Chris' blog, there's mention of an interesting and new-to-me joinery fitting technique: using a flush-cut saw to kerf in a joint.

I'd love to learn a bit more about this technique and its context of use, as it's not something I've encountered elsewhere yet. My current assumptions from Chris' descriptions are that this is used when fitting a tenon shoulder, where the flush cut saw is able to use the mortise shoulder as a reference plane. Does that cover it, or have I missed something?

Some questions on my mind:

1) All (again, western) mortise-and-tenon joinery discussion I've seen to-date has focused on using either a shoulder plane or a chisel to adjust tenon shoulders. Where does kerfing fit in the range of fitting techniques? The opportunity to use the mortise shoulder as a reference plane seems pretty powerful.

2) Are there situations where kerfing is particularly appropriate, or inappropriate?


(**) My curiosity piqued, I dug around for going prices Yataiki saws. This expression resulted: It seems the collectors have arrived.

When you try a Miyano saw, you'll understand- they ARE better. But, once a famous maker dies, the prices skyrocket. When Miyano was alive and working you could buy a ryoba saw for around $500 - I know that might not seem cheap compared to the mass-produced impulse-hardened saws. The regular Japanese replaceable saws are fine, and i would recommend them. The Miyano saws are in a class by themselves though.

When Miyano (Yataiki) was still alive but had stopped working, the prices of remaining stock climbed to the $1500 zone. After he died the prices in Japan are now over $2000.

I picked up a couple of NOS Miyano saws on Ebay last month, saws which had been imported to the us in the 1980's. I obtained each saw for about $700, which I considered a deal. I jumped at buying them even though i also think $700 for a handsaw is kinda insane. I will only use these saws on special projects though. I still haven't put the handles on.

To put it somewhat in perspective though, a handsaw, made by hand, involves a substantial amount more work than a plane blade or chisel, so, apples to apples, a handmade saw should cost more than a handmade plane, but they rarely do.