Another banger from Akame natural farming school.

Cool people I met:

• Shou, speaks French, English and Japanese, lived in France for five years

For the practical sessions:

• I learned to cut wood with a two-sided saw, and how to make basic angled cuts (ie diagonally across a 6x6x2cm cross section in a rectangle, placed so it is not symmetric).
• I spent about three hours taking a chisel from chipped and blunt to sharp and mostly straight. Then, I used this to smooth another angled cut I made.

You can find books about Japanese joinery, specifically on tsugite (horizontal joins) and shiguchi (corner joins). They recommended one (in Japanese) called 木造建築の継手と仕口 (wooden building: horizontal joins and corner joins), which should go for about ¥3000 (don't believe Amazon).

Practical

Two handed saw. Cut parallel to the grain with the big teeth, and perpendicular with small teeth. However, you can use the small teeth in any direction to mark a starting cut with a knuckle against the blade face (like a kitchen knife).

To cut straight through a cross section, you mark your cut around all four sides, then cut twice inwards to the middle diagonal from two diagonally opposite corners. Phrased alternatively; if the subsequent corners of a plank are 1,2,3,4, you cut from 1 through to the line (2,4) from 2 to 4, and then cut from 3 back to the line (2,4).

Sharpening.

• Timing. Ideally correct whetstones and then sharpen before each carving session.
• Kinds of blocks
  • Diamond stone. For reshaping the blade and removing chips. Do about 100 slides with the blade and check how it looks.
    • To correct a chipped blade, grind until the chips are not visible, doing your best to maintain an even blade shape.
    • To correct an uneven (bowed or non-flat) blade, press harder on the back (flat) of the blade above where the excess of metal is. Ensure the block itself is relatively flat.
    • To correct a rounded blade, grind evenly until the angled side has a consistent shine (that is, it reflects light at the same angle; its reflection should not shine in different places as you rotate the blade).
  • Whetstones. For sharpening a straight, un-chipped blade. Start with the coarse grit (low number) and move up to a fine grit.
• Blade sharpening and shaping technique.
  • Wet the block. Hold the chisel so the flat face is up and the angled face is down. Press the blade down from the flat face so the angled face is as flat on the block as you can (parallel to the knife edge). Hold so it's roughly diagonal to the block. Move in small motions forwards and backwards, moving around the whole block so you don't favour any particular spot. Then, put the flat face flat against the block and move it from side to side (not forward and backward) only 5-10 times, and carefully check that there is not any residual metal bend to either side of the blade tip.
• Correcting a whetstone.
  • Your whetstone face will become bowed and uneven over time. To correct this, place the diamond block against the whetstone with a little water between, and move the diamond block in circular motions against the whetstone. Repeat until flat.
• Correcting the diamond block.
  • Sometimes the diamond block itself becomes uneven from reshaping a blade. To correct this, find a flat concrete brick or pavement. Sweep it to remove debris or small rocks will carve scratches in your block. Wet it, then move the diamond block like you would a whetstone to correct the stone. You're probably gonna have a smooth-feeling diamond-buffed piece of concrete after this.

Discussion and theory

For the record, all the penis / anatomy references are my own, because I think they're genuinely helpful for visualising.

The joint in question: koshikake mechigai kamatsugi

• mechigai, male part
• The head of the male part (like let's not pretend it doesn't look like a penis, because we can steal its anatomy) has two funny angles to it:
  • The lateral faces of the head are angled to maintain the integrity of the surrounding wood (the surrounding wood of the female is thicker).
  • The rear faces of the head (ie behind the ears) is angled slightly, which makes it easier to insert the male piece to the female.
• The upper face of the female part under the male head is deeper than the face under the male's neck (aka penis shaft). This is an error tolerance, largely for insurance / meeting building code; if the male head does not fit properly in the female, then this might introduce stress points where it does make contact.

In general, the greater the surface area, the stronger the joint. However, due to limitations in cutting by hand, we suffice with less.

For any complex male-female connection, you should do a small guide cut to serve as your templates. The wood should be the same girth as the actual wood. Then, you use the male guide to trace the female cut lines, and use the female guide to trace the male cut lines.

Joints are cut away with a series of blocks.

Given a desired shape to cut from a beam, how do you cut it?

• For simple rectangular or triangular cuts, you saw the edges and then chisel in between. Sawing first helps limit the collateral damage when you chisel; if the wood splits, it only splits up until the nearest saw cut.
• When you can't make the lines with a saw (ie in MF joins), you remove them by dividing the to-be-cut space into squares, ordering them, then cutting in the order 1 3 2 (three squares), 1 5 2 4 3 (five squares). You're less likely to chip away big chunks which might split the wood.

Wood beam protection and sewari. Interestingly, for all beams, you will notice that they have a slit in one of four sides (or even if they are still a round log). If you cut a small slice of a log or beam, leave it till winter, you'll notice it cracks. This is due to the moisture more readily being absorbed by the outer layers, which (I think) leverages the wood against itself and causes a crack. To avoid this, you cut a slit down one of the four sides to almost the centre, which allows the pressure to dissipate. This cut is called sewari. If you look on the logs or supports used to build old temples, you'll notice these cuts too.