Congratulations — you are now the proud owner of a Japanese plane. There is just one small catch: straight out of the box, it probably isn't ready to perform at its best.
Don't worry. This is completely normal. Japanese planes are designed to be tuned and fitted before use, a process often referred to as fettling. The blade, chip breaker and wooden body (dai) all need to work together, and a little careful preparation can make an enormous difference to the way the plane cuts.
Tuning is not simply a one-off job, either. A Japanese plane is a tool that benefits from occasional adjustment throughout its working life. Timber moves, blades wear and sharpening gradually changes their geometry. Learning how to make these small adjustments is part of learning how to get the best from the tool.
We have put together a five-part video series covering the main stages of tuning a new Japanese plane. We will also be adding supplementary videos to explore particular techniques in more detail and cover adjustments that may not have been necessary on the planes featured in the main series.
Ura, Meet Kanaban. Kanaban, Meet Ura.
The ura is the hollow-ground area on the back of a traditional Japanese blade. Before you begin working on the bevel, it is important to establish a flat, polished surface around the ura at the cutting edge.
For single-bevel blades such as Japanese plane blades, chisels and many knives, we strongly prefer using a kanaban. A kanaban is a reliably flat steel plate used with a fine abrasive to lap and polish the back of the blade.
Because the plate provides a known flat reference surface, it gives you excellent control over the area being worked. The aim is not to grind away the ura unnecessarily, but to create a clean, flat and consistent surface immediately behind the cutting edge.
Polishing with the Kanaban
One of the great advantages of a kanaban is that it can produce an excellent finish without requiring an elaborate progression of ultra-fine stones or polishing powders.
With a little practice, careful control of the abrasive and the right amount of water on the plate, you can develop a remarkably fine and even polish. The key is consistency: keep the blade registered flat on the plate, use controlled strokes and avoid concentrating all your pressure in one area.
Take your time. Removing more steel does not necessarily mean you are making faster progress. The goal is an even surface that supports a sharp, predictable cutting edge.
Straight and True
Establishing a truly flat back is one of the most important steps in preparing a Japanese plane blade. No matter how carefully the bevel is sharpened, the quality of the cutting edge ultimately depends on the two surfaces meeting cleanly and consistently.
A flat back also makes it easier to control the profile of the cutting edge and helps the chip breaker bed against the blade correctly. Any high spots, hollows or uneven polishing close to the edge can make sharpening more difficult and prevent the blade from performing as well as it should.
The goal is simple: a flat, polished and consistent surface at the cutting edge. It may take a little patience the first time, but once the foundation is established, future sharpening and maintenance become considerably easier.
Like most aspects of Japanese tool preparation, this is less about rushing towards a perfect finish and more about developing a repeatable process. Work carefully, check your progress often and remove only as much material as necessary.
