Thursday, December 22, 2011

Just Scraping By

I have long been an admirer of Ming and early Qing period Chinese classical furniture. Not only is it aesthetically satisfying, but the pieces very much appeal to the purist in me as works of pure joinery. Many Chinese furniture pieces were in fact built to be knocked down for transport, and using glue was frowned upon and minimized. The way these pieces have traveled through time to the present with such grace and durability is a testament to the way they are made.

One thing that has always struck me though is that fact that classical Chinese furniture is made from extremely hard and dense wood species, like Rosewoods (huanghauli) from the dalbergia group, or Zitan a variety of pterocarpus, etc. Many of these woods have interlocked grain that are very difficult to work with hand tools. I have long wondered how Chinese craftsmen achieved such sublime results given the apparent crudity of their hand tools. I find these woods difficult to work myself even though I have the benefit of carbide and powered machinery for certain steps in the making process.

The Chinese used hand planes, however the ones I have seen do not particularly impress at a glance, at least as far as their blade metallurgy is concerned - often just stamped and heat-treated high carbon steel. Here's an example of a Chinese plane, from Shanghai:

Chinese planes are pushed, unlike Japanese planes which are pulled. The Japanese adopted the plane from China and made changes to it, including removing the handle and relocating the blade towards the front end.

I had thought that Japanese blacksmithing and laminated blade techniques likely also stemmed from China, however I had never seen reference to a Chinese plane with a laminated blade - until recently. I'm currently reading the work by Nancy Berliner entitled, Beyond the Screen: Chinese Furniture of the 16th and 17th Centuries:

Contained within is a section by noted specialist in Chinese classical furniture Curtis Evarts, a chapter called "The Furniture Maker and the Woodworking Traditions of China". On page 69 there is a the following illustration from the 15th century work the Lu Ban Jing:

Chinese planes, I might point out, are pushed, not pulled. The above illustration I have seen on several previous occasions, including in a translation of the original text. I'd always noticed two things about that picture - the craftsman planing the table top, and the hexagonal table in the background. We can also see a chisel, a mallet, and a bow drill in the illustration, along with another curious looking tool which looks a bit like a miniature rake or comb.

The plane in China before the two-handed push plane appeared was the spear plane, which the Japanese also employed, and presumably adopted from China. The push plane developed some time before the Ming period (1368~1644). In the 1637 (incorrectly ascribed to a 1609 date by Evarts) technological treatise Tiangong Kaiwu (天工開物) by Song Yingxing, which may be loosely translated as "The Exploitation of Works of Nature" there is specific reference to the push plane:

"[The blade of] the common plane is made sharp with one inch steel laminated onto its cutting iron. It protrudes the smallest fraction at an angle from the opening of the [lower] surface, and therefore [it is used to] smooth flat the surface of wood."

Aha! So at one point in time the Chinese had laminated steel-iron cutting tools! That was a most interesting reference to come across. I wonder if any of those older laminated cutter are in existence anywhere? My impression is they're not made any longer for Chinese hand tools. Interestingly, original copies of Tiangong Kaiwu are now extremely scarce in China - however some were preserved in Japan, which indicates information about many Chinese technological practices was available in Japan at an early date.

As Evarts notes in Beyond the Screen,

"These references indicate that the quick and accurate bao evolved from the early planing knives and the spokeshave plane, and that is was not known in Japan before the sixteenth century, when the push plane was introduced from China. Although later Japanese woodworking tools are renowned for their excellent laminated-steel blades, it is clear from various passages in the Tiangong Kaiwu that Chinese ironsmiths in the late Ming period were still well-versed in the art of producing high-quality blades with steel forge-welded onto cutting edges. The dependence of carpenters on ironsmiths is made clear in Pu Songling's lines, "Ax and adze handles are cut and shaped by themselves, but plane blade, gouge, and saw [blade] all cost them money."

Later in the passage from the Tiangong Kaiwu there is a reference to another plane:

"... for scraping wood extremely smooth is called a "centipede plane" (wugong bao). Ten or more small knives are clinched within a wooden handle and look like centipede legs."

That my friends is what that funny little tool depicted in the Lu Ban Jing illustration above. The term wugong bao zi is written in Chinese characters as: 蜈蚣鉋子. The word for 'plane', baozi (鉋子), is often shortened just to bao (鉋). To add to the confusion, in modern simplified Chinese the character for plane is now '刨' or '刨子'.  This modern replacement is a similar character, containing the same element '包', (meaning, wrap, envelop - actually the character derives from a pictograph of a fetus encompassed in a placenta/the womb), however the radical 'metal' (金), has now been replaced by 'sword/knife' (刀). Am I digressing too far? Perhaps...

Anyhow, the same character, '鉋', is used in Japanese also to mean 'plane', and in fact the word for centipede in Japanese (muka-de) is also written as 蜈蚣. The 'centipede plane' however does not seem exist in Japan as far as I can tell - if it was adopted, its use never became widespread. There may be one or two examples in the Takenaka Tool Museum in Kobe - if any readers happen to visit the museum, take a look and let me know.

This is what a centipede plane looks like:

Another one:

The blades are sandwiched into kerfs, or, in some versions, between  intermediate spacers:

The centipede planes come in various versions, just like other woodworking planes - here are some rounding/beading centipede planes:

In this illustration one can see, second from left, a centipede plane for concave surfaces:

These come large and small:

Apparently, many craftsmen make their own centipede planes and these tools are still a part of the present-day Chinese woodworker's set of tools. The blades are fitted - apparently the last one in seems to wedge the lot into place, and then the cutting surfaces are dressed flat (or to some other required shape) with a file. Then each blade is beveled slightly. Seems like it would be a nightmare to set up such a tool, especially the non-flat/non-straight versions.

I was thinking about reasons why the Japanese didn't adopt such a plane, at least not on a wide scale. Perhaps the fact that Japan was pretty much closed up to trade during the Edo period (1603~1868), which followed shortly on the heels of the importation to the country of Chinese planes and other technical items, and that there are few indigenous wood species so hard and difficult to work as the Chinese huanghuali and zitan - wood that had become scarce and that China needed to import from the 13th century or so. The Japanese flowering of traditional arts which occurred during the Edo period would be one in which few imported materials of any kind would play a role. Even today, items made from ebony (kokutan) and other hard exotics are not particularly commonplace. Anyway, it' a theory and nothing more. I'd be interested to give a centipede plane a try one day, but meanwhile, when working with Ipe, curly Bubinga, vertical grain Jatoba, etc., I don't feel like I am straying too far from traditional practice when I resort to scraping the wood.


  1. Its a good thing that ancient practices are preserve.

  2. The article is very thorough in discussing the Chinese and Japanese hand planes. Thanks for sharing.

  3. Gentlemen,

    thank you so much for your comments!


  4. Trade with China and Korea was active during the Tokugawa period in some products, including swords. Avoiding Western imperialistic dominance was probably their core motivation, not avoidance of regional trade. (See Ronald Toby's work.) I suspect technology transfers were also driven by need as well, so if Japanese carpentry did not need a solution, and if the existing market did not promote more efficient or cheaper solutions, innovative solutions from the rest of Asia were likely ignored.

    1. Thanks Joe.

      Are you referring to Toby's work State and Diplomacy in Early Modern Japan?


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