Japanese carpentry

Japanese carpentry was developed more than a millennium ago that is known for its ability to create everything from temples to houses to tea houses to furniture by wood with the use of few nails.
Though there is a core practice shared by all Japanese carpenters, defined by a vocabulary of tools and joints and a method of working, a carpenter will typically identify with one of four distinct carpentry professions. Miyadaiku (宮大工) practice the construction of Japanese shrines and temples, and are renowned for their use of elaborate wooden joints and the fact that the buildings they construct are frequently found among the world's longest surviving wooden structures. Teahouse and residential carpenters, known as sukiya-daiku (数寄屋大工), are famed for their delicate aesthetic constructions using rustic materials. Furniture makers are known as sashimono-shi (指し物師), and interior finishing carpenters, who build shōji (障子) and ranma (欄間), are termed tateguya (建具屋).
Though it is rare to find a sashimono-shi or tateguya practising outside of their field, it is not uncommon for a carpentry workshop to work simultaneously as both miyadaiku and sukiyadaiku.
The tools commonly used by Japanese carpenters are divided into a few basic families, within which there are found a multitude of variations and specializations geared toward particular tasks:
Though a carpenter will typically fashion handles and woodblocks and set and sharpen their blades themselves, the blades themselves are forged by steel smiths and provided unmounted to the carpenter. Japanese steel has long enjoyed a high level of refinement, without which the fine surfaces and detail for which Japanese woodwork is renowned would not be possible. The blades used in the Japanese chisel and the Japanese plane shares similar constructive principles to the Japanese sword. A thin piece of extremely hard blade metal called ha-gane (鋼, lit. 'edge metal') is forge-welded to a softer piece of metal called ji-gane (地金, lit. 'base metal'). The function of the softer base metal is to absorb shock, and to protect the more brittle ha-gane from breaking. This technology allows for the use of steels in the hagane which are harder than in use in Western chisels, typically Rockwell 62 and up, and also allows for the honing of a much finer edge than is typically known in carpentry outside Japan. When sharpening a blade, a Japanese carpenter will typically use three or more whetstones of varying coarseness, progressing from the roughest stone to the finest.
The blades of both planes and chisels are distinguished by the hollow, ura in their flat side. This hollow portion has a number of functions. The primary function is that it ensures a high degree of flatness when sharpening, in that when the flat side is polished it cannot rock or develop a curve because it is only contacting the stone on either side of its width. This then improves the precision with which cuts can be made by the chisel, and in the case of planes ensures smooth contact with the wedge and therefore even support across the full width of its blade. The hollow also greatly reduces the amount of metal needed to be removed to achieve flatness on the back of the blade, which shortens initial set-up and subsequent re-sharpening considerably. Secondly, in the case of chisels, it reduces the frictional resistance as the chisel is driven into or extracted from the wood. Thirdly, the interaction of the leading edge of the hollow with the edge of the blade is a changing relationship as the tool is re-sharpened. With plane blades, as the edge is sharpened down to the rim of the hollow, the edge can then be 'tapped-out' (ura-dashi), a process where a pointed hammer is used to depress the ha-gane downward slightly along the bevel of the blade. When the blade's back is re-flattened after ura-dashi, the hollow is re-established; thus the hollow acts as a sort of gauge for sharpening as a means of prolonging the life of the thin piece of cutting steel as long as possible. This in turn tends to keep the geometry of the blade consistent over time, which keeps it fitting the dai over time.
There are many types of steel used for the ha-gane of Japanese planes and chisels:
The traditional Japanese vise was a wedge of wood tied to a post with a coil of rope. The wood was inserted under the wedge and the wedge hammered down.
Vises of any sort are used far less in traditional Japanese carpentry than would be the case for equivalent tasks in the traditional crafts of the West. Many tasks in Japanese carpentry associated with building, involve very large pieces of timber, and in general, the weight of the timber and of the carpenter are used to stabilize the piece on which the carpenter is working. For this reason the carpenter's horses used in Japan are much lower than their Western counterparts, and carpenters must always position themselves over their work. Much of the work on smaller pieces of material can be done in the seated position, and relies on the fact that the saws and planes both cut on the pull stroke, enabling stabilization of the work using the body or shooting board.
Woods used in Japanese carpentry and woodwork, as well as tool construction, include sugi (杉), akamatsu (赤松), hinoki (檜 or 桧), Camphor Laurel, Magnolia obovata, keyaki (欅) and kiri (桐).