Getting a kanna ready to use will make it very personal for you and you will understand the whole concept as you sharpen the blades, condition the blade chute and adjust the sole. Again, go to the
archives of the japanesewoodworking forum for more tips and here is a
diagram of the parts of a kanna
You will need some tools to pare down the blade chute and reduce the blade mortise bed plus some other scrapers or files or fine chisels to get into the corners. Some of these tools you may have
around your shop, and others you can make. When you start to work on the blade chute I suggest that you retract the metal pin from the dai. This gives you total access for working on the blade bed
area. You can do this by grabbing the pin in the middle with some pliers and tapping the pliers with a hammer so the pin slides out the hole on one side of the dai.
I use a scarper, not a chisel, to pare the bed down. My scraper tool is 1/2 inch wide and about 1/16th inch thick and sharpened at a 90 degree angle, or straight across on a grinder and made from an
old Stanley chisel. This gives me a sharp edge as a push scraper. It is nice to have a decent handle on the tools because it is easier on the hands.
Here are some reference photos of a kanna.  Dai top, Dai bottom, Blade chute, Blade mortise, Tsutsumi ledge, Blade throat.
A few thoughts on setting up the kanna
I first get my blades all set up if they need it by performing uraoshi and uradashi (tapping out and flattening the main blade ura or hollow side) plus flattening the back of the sub blade. The two
blades should be perfectly flat on the urashiki side right down at the cutting edge and the ura landing at the edges or the main and sub blade should fit perfectly flat against each other at that edge just
like they will sit in the dai when set up to cut.. Finish by sharpening them just like as if they were already in a working kanna. I work on the blades first because the blades dimensions and shapes will
change during this first step so I want to do this sharpening first because it affects the length of the blades and how much projects beyond the sole of the dai when it is cutting. This is all in direct
relation to how tight the blade fits in the dai chute when the blade is protruding and beyond the sole while shaving wood. There is no substitute for a tight fitting blade and a perfectly shaped blade
chute and bed.
Next I like to flatten and level the sole of the dai from corner to corner by taking out any twist in the dai. By looking at the corners using winding sticks or matching straight edges and working in from
the corners to create a flat and even surface on the sole. Do this before trying to fit the blade. Also you should set up your wave pattern with a raised area in front of the blade and one at the rear of
the sole.
Note: In the Japanese thinking, the rear and the front of a hand plane is different then in the U.S and European tools. Think of it this way. Hold the kanna in front of you as if you are going to use it,
pull it towards you, if you are right handed allow the kanna to come at rest at your right side. With the kanna at your side look down. The end of the kanna towards the way you are facing is the front,
the end that is facing behind you is the rear.
Once you have set up the sole you can work on the blade mortise and blade chute. In most cases the blade was partially fitted into the dai, so chances are that most of the shrinkage will be in the
width. The blade chute on either side can be widened to the width of the blade, but do touch the underside of the top rail of the blade chute. You can adjust for the thickness of the blade by paring
down the blade mortise bed but remember, do not touch the underside of the top blade chute rail. This underside establishes the angle the blade fits into the dai and the dai maker was very careful in
establishing this angle with a special saw.
Before you pare down any of the bed, work slowly and methodically on the width of the blade chute. Try to get the blade to fit by paring down the sides so the blade will slide down hand tight to
about 2-3 centimeters from the sole.  I use camilla oil on a rag as an indicator in the fitting process. Rub your oiled rag on the bevel side of the blade and the blade sides and on the bevel itself so as you
drive in the blade you can see where the oil rubs off on the wood. This indicates where you need to pare. If you have trouble seeing the sheen of the oil on the wood you may want rub a pencil on the
oiled surface of the blade, this way the graphic from the pencil will float in the oil and you can see the blackened oil that has rubbed off easier. Rubbing a dry pencil on a dry blade really just colors the
blade and does not rub off easily, but in the oil the graphite rubs off and transfers nicely.
After you have fine tuned the width factor, stop before you have made the blade sloppy or give it too much lateral play, next you can work on the blade bed. Use the oil or oil/graphic on the back of
the blade and each time you drive the blade into the chute you will see where the blade touches the bed and where you need to pare.
As you are working on reducing the bed keep an eye on the sides of the blade chute as you will see that as the blade advances down the chute with each fitting, the sides will need some more attention
Go slowly with the paring procedure because of course you cannot add wood and if you take off too much the blade will be loose. Things get critical towards the bottom of the blade mortise where
the blade throat opens to the sole of the dai. If your dai has a tsutsumi ledge that supports the blade bevel and if in fitting the blade the tsutsumi has not been pared and fitted properly, driving the
blade down hard can push the wood out and distort the sole contour or make a crack in the area on the sole.
As you are working at paring down the chute and bed, and the blade is getting close to the bottom of the mortise, work very slowly and carefully not to stress the wood and force out the bottom of
the sole. Use the oil/graphite on the
blade bevel when fitting to indicate where the tsutsumi needs to be pared and shaped. It will need to be reduced in thickness to some degree, the dai maker left it
with extra material knowing that you, the owner, would pare down this area too. Use your straight edge to look at the sole profile without the blade inserted and then look again with the blade driven
down to see if a bulge appears. If there is a bulge, lightly mark the high area with a pencil. In Inomoto-sans classes he has students make a dai without the tsutsumi because it is easier and does not
require special tools to pare out the shelf or ledge.
If you crack the ledge and split the sole beneath the tsutsumi, all is not lost, you can simply open up the dai in the manner of a lower grade regular dia. But it will be a good experience for you to try
to work with this tsutsumi as it is. All this will take you hours and maybe days, but good luck.