Training for Mud: Apprenticing Japan’s Plaster Craft

By Emily Kathryn Reynolds (adapted from The Wooden Post, vol 14, December 2019)

Editor’s Note: Japanese craft has long relied on a seamless network of craftspeople each team relying on the expertise of others to complete the total. Mud walls are the perfect compliment to natural wood joinery.

I have been asked to update Kezuroukai USA readers about my apprenticeship with sakan in Kyoto, the craft responsible for the earthen walls that come between the wooden framework of Japanese classic architecture.

Mine has turned into a very unusual apprenticeship.

When I returned in Spring of 2016, I thought I would be here for two years. My second year in, I realized I must stay on at least another three years to feel satisfied. It takes at least five years to gain solid competency around producing the right brown coat under any circumstances; that is, the layer before the thin finish, which must be applied as perfectly as the finish will be. And so, I found myself a visa – a three-year PhD program at Kyoto Institute of Technology (KIT). Three days a week I train, three days a week I am at school.

Now in my fourth consecutive year of training, I have changed companies. I spent my first two years with the company Shikkui Asahara, with master Asahara Yuzo, also in Kyoto. My current oyakata (master) is Sato Hiroyuki of Izutsuya Sato. He is a fourth generation plasterer. His company specializes in walls for sukiya, temple, and tea house architecture. Unique circumstances like mine are not foreign to Sato oyakata, who sometimes introduces himself as a professional choral singer. He also holds a “paper PhD” (ronbun hakase) for six studies he has conducted over the years with various professors at KIT, pertaining to sakan earthen material and physical movement.

Izutsuya Sato employs two elders in their mid-70s, two men in their mid-40s, and me. I am blessed by the support of each of these mentors, senpai. Despite my part-time status, they expect me to be a full-on member of the team. Not being able to train every day is challenging, because I would be more skilled by now if I could. But my senpai invite me to make the most of the days I show up. They put me to task when they know something is unfamiliar to me. Every job site has unique requirements, be it a restoration or new construction. How we prepare the substrate will vary according to how the wall will be finished. The season and weather will also affect how we prepare and apply the materials. Encountering as many sites as possible teaches me to approach each project according to the circumstances of the moment. Over time, I also witness patterns in how each of my mentors approach their work. This helps me identify habits I want to incorporate into my own patterns. I get more exposure, and gain confidence.

Training for Mud: Apprenticing Japan’s Plaster CraftSpending my first two years with Shikkui Asahara was amazing. They work almost exclusively with temples and other culturally significant structures, and occasional private clients who appreciate their offerings. I never worked with anything but natural materials there. That is extremely rare, even in Kyoto. Now with Sato, I continue to work heavily with earths and shikkui lime, but I’ve also gained more familiarity with industrial material applications; working at times with cements and with synthetic plasters. At times we build up a series of synthetic and gypsum applications over drywall, finishing with shikkui lime or earth. With this now also in my training, I feel more prepared to approach any type of jobsite into the future.

The first step in restoring an old mud wall involves removing layers of plaster to a level that is not weathered and damaged. Experience over time teaches you how not to remove “too much” of the old plaster. In every step of the process, the aim is to make the next step easier in order to expedite the work. Various skills are called upon to bring the wall back to a finish. Is there a need to fortify the edge to prevent separation of mud and wood? To what degree should materials be sifted for each application? Working with experienced mentors provides the know-how. Their vast hours of training and broad range of experience inform every decision. It might seem, then, that plastering for a new structure would be more straight-forward, and for the most part that is true. However, new materials appear on the market, and each must be handled accordingly to achieve desired results. The experience sakan have gained over time – transitioning to industrial materials while retaining their roots and aesthetics – amounts to a treasure trove of knowledge. This knowledge can help reverse the current trend, shifting architecture’s industry standards to include relatively unprocessed, natural materials.

While I dream of fully earthen architecture becoming normal around the world once more, I am preparing for a mere inclusion, which will require many skilled professionals. The perception about mud walls can be this: rugs stay clean while the walls get re-finished with earthen plaster.

Training for Mud: Apprenticing Japan’s Plaster CraftWe now know that there are global and personal health risks associated with the building practices that have developed over the last century. Earth has served us as a material in architecture before, and it would behoove our bodies to rely upon it once more. The personal health aspect is much like choosing to consume organic or wild foods; there may not be a scientifically quantified percentage of improvement in quality of life (yet), but the “user” feels a difference. When someone finishes or re-finishes their home with earth plaster – be it conventional condo or strawbale house – people tend to perceive a deep level of relaxation there. In Japan, I often hear people exclaim the old-style homes are “kimochi-ii,” pleasant feeling. Elders quickly point out that they compliment Japan’s humid climate. This is because the porosity of earthen walls absorbs excess moisture in the air. This can prevent unwanted issues, such as mold. And on days when the air is dry, the walls will release moisture. Not to mention, the work is beautiful.

Some sakan are actively promoting their work with natural materials on social media. Seeing this inspired me to document how sakan are working on site, which resulted in my second book, Sakan at Work: Japan’s Natural Plasterers. It is self-published, and so at this point is only self-distributed. A digital version will be coming soon.

I am inspired by Kawai Takami of Suikoushya International Craft School, in Kyoto. Here, carpentry is taught in English to a small group, for one month. Could this be replicated for sakan? I will be exploring this, and maybe manifesting it, over the next several years.

(The first book, Japan’s Clay Walls: A glimpse into their plaster craft, can be found on Amazon. For Sakan at Work, please contact me directly at EmilyKathrynReynolds@gmail.com)