The JS-4 works perfectly for cutting back protruding joinery including; dovetails, dowel joints, mortise and tenons and much more. There is ZERO set to the fine teeth (32/inch) and therefore it is almost impossible to score or scratch your reference surface. We do not believe you will find a better performing or easier to use flush cut saw anywhere. The JS-4 cuts on the PULL stroke and is extremely fast cutting. You have to use this saw to believe it.
There should be a law requiring every serious woodworker to own this saw. The capabilities are astounding. This is a fully flexible saw blade with 32TPI with NO saw set. The resulting cut is so smooth, the clean-up is a breeze if required at all. (One tip you will want to remember, remove dried glue from your protrusions before using this saw to preserve sharpness and increase blade longevity.) We cannot recommend this saw high enough. It is simply a fantastic tool.
Japanese Saws cut on the pull stroke, and because the blades are under tension during cutting, the blade thickness can be much thinner than European heritage saws. A thinner blade means less material is removed and requires much less effort to use. With a little practice, your cuts will look like they were made with a laser.
In soft woods, Japanese Saws cut so efficiently, it is hard to believe it is made by hand. In hard woods, as in all hand sawing operations, let the saw progress at its pace and apply very little downward pressure. Cuts are started at the back of your stock as you pull forward. Aggressive and impatient users will invariably break teeth on these saws which defeats the purpose of owning a precision saw.