Sumi-kiri - chopping charcoal for bladesmithing

Read more about the museum project here: http://islandblacksmith.ca/2017/01/building-traditional-swordsmith-forge/
See more charcoal making videos here: https://www.youtube.com/playlist?list=PLBJ5AOs7cMwAi0VcrZt-tyGIsrOUrzhyj

A sample of the sumi-kiri process; charcoal chopping, screening, and sorting techniques, and may offer some useful details for astute observers.**

Traditional Japanese swordsmithing forges are fueled by softwood charcoal which is first chopped, screened, and sorted into several sizes for different stages of the forging process.

The charcoal is chopped and then processed through four sizes of screen, the largest is for tanren, the second for hizukuri (I tend to use the largest for hizukuri as well and keep the second size mainly for yaki-ire), the third size isn't highly useful but may be crushed into fines or saved for tatara, the fourth is the fines for lining the bottom of the forge, and the remainder is dust for mixing into yaki-ire clay or for brasque refractory.

Measurements for the screen sizes are given in sun-shaku and the type of charcoal they keep in is listed rather than what they allow to pass through.

3.03022 cm
= 0.1 shaku（尺）
= 1 sun（寸）
= 10 bu（分）
= 100 rin（厘）

**Three things to note, 1. after setting up, i moved the camera orientation 180 degrees and rather than move all of the charcoal i moved only the chair to the opposite side, but for efficiency it is a good idea to have the charcoal at the left side within reach of the non-chopping hand...2. rather than chopping directly into a screen as i do, the normal procedure is to chop onto the tarp and then rake most of the largest charcoal off the top by hand before screening the remaining pile (https://youtu.be/3DdXdxSb3vE)...3. also, some of this charcoal is quite soft having been heated too quickly in the kiln or overcooked so it looks more crumbly than it should.