Japanese style box bellows (fukisashi/吹差鞴) reached their current and finalized form by about the sixth century. They are constructed almost entirely of wood and allow a smith to supply a highly controlled air blast to the forge by pulling and pushing the handle slowly back and forth. Using dual chambers and two sets of valves, the air is supplied on both the push and the pull stroke, and the blast may be highly intensified or stopped in an instant as needed by the smith.
Three reasons why *you* need a Japanese swordsmith’s style fuigo (鞴) box bellows for forging blades:
- Better Fuel Efficiency – As soon as you stop moving the handle the air instantly stops, saving fuel while you are at the anvil. This becomes really important with larger stock as forging heats can be quite long.
- Instant Fire Recovery – Unlike with most electric blowers or a western hand cranked blower the fuigo blast can be extra strong at restart and then drop to a suitable level in a few seconds once the fire has revived. This reduces time in the fire and can provide graduated heating, stronger before the oxidizing temperature level has been reached, and more reducing once the steel starts to glow.
- More Reliable Yaki-ire – While moving a clay-coated blade through the fire, the fuigo can be quickly blasted to lift and separate the charcoal, preventing it from knocking off weak areas of the clay.
…and besides that, they sound cool and add another rhythm to the forging process. So if you are a bladesmith interested in historical methods, consider the Japanese swordsmith’s fuigo for certain stages of your work.
Note that the fuigo pictured here is a roughly constructed prototype designed to fit the space constraints of my current setup and should not be relied on for proper proportion or measurement.
In a future post I will discuss some of the details of construction and function. (spoiler alert: blacksmith’s beware of small traveling kinko or ikakeshi (鋳掛師 ~tinker’s) bellows that sometimes come up on auction sites…check those measurements or prepare to pump vigorously!)
Read more about fuigo: islandblacksmith.ca/tag/fuigo/
For those of you working out designs, here is a video for study, John Burt reveals some secret details of fuigo construction based on an antique used by a saw smith Hirota~san: youtu.be/3Ecetg1B7y4
Update: Gabe at Granite Mountain Woodcraft has some historically accurate beta plans online: granitemountainwoodcraft.com/2015/07/08/designing-fuigo-japanese-box-bellows/ and was recently able to examine the original antique fuigo used to model the one in the video above: granitemountainwoodcraft.com/2016/04/23/hirotas-fuigo