Yesterday I returned from a four day Golden Week ceramic trip to Numazu in Shizuoka, near Mount Fuji and the Izu Peninsula. The in-law ceramics senseis organized this annual trip to use a wood-fired oven to make special bizen pottery.
For three days and nights, we heated a wood kiln until it reached 1200 degrees celsius, taking turns feeding it. It will take another three or four days for the kiln to cool down, so a return trip is necessary to take out the pottery.
Here are some photos that depict some of the process. Below are the 18 or 20 pieces I made: mostly flower vases with lattice tops, ten small round plates, and four rectangular plates.
Some of the ceramics were wrapped in rice straw, which produce unpredictable effects.
The kiln is very carefully filled with ceramics before the large arched opening is filled with numbered bricks. It was incredibly how much pottery can be tightly packed inside, with small spaces separating them to make sure the heat can flow through the oven. Sensei uses a small hand mirror to make sure that everything is spaced properly.
This is what the kiln looks like full, before firing. Rice husks are used to keep the pottery from sticking to the shelves.
The kiln god is offered a trio of sake, rice and salt. The senseis and students said a silent prayer that all would go well. In wonderful Japanese fashion, prayers are heartfelt and brief. And then the fire is started.
Throughout the 55 hours of firing, a careful record of the temperature is kept at 30 minute intervals. For the first 10 hours, the kiln is heated at 30 degrees per hour, later rising to 50 degrees per hour.
As the temperature heats up, we took turns feeding the oven every three or four minutes. By the time it is very hot, the logs catch fire when they touch the brick walls of the kiln. The action shot at the top of the post shows this off.
Because there were 8 to 10 of us at all times, there was also plenty of time for relaxing, listening to the birds tweet, and eating well. My sister-in-law came on the third day, and made a delicious yakisoba on a barbeque, and later grilled fish, chicken and pork. We also ate multi-course meals prepared by my mother-in-law, including Thai-style curry, eggs and sausage, pasta with meat sauce, and many salads. My small contribution was to make margaritas with fresh Hiroshima lemons.
The Numazu ceramic center has six or ten kilns spreading down a hillside. The owner, a gentleman in his 80s, delivered three pallets of wood for our kiln. Amazingly, his 90+ mother still farms and arrived one early morning to construct bamboo supports for the small vegetable plot outside our cabin.
This is a view of the kiln area at night. You can see that the building is made of scaffolding pipes, a tin roof and lots of fluorescent lights.
Below you can see what the kiln door looks like closed. The numbers on the bricks help with sealing off the oven. And you can see the heat glowing inside.
Towards the very end, sensei opened a brick so we could see the fire dancing inside. It was spectacular.
The final step was to seal off the kiln, making it air tight. Then, we opened two bricks and poured bamboo coals inside to create more unpredictable effects on this unglazed pottery. Although sensei earlier joked about “backdraft,” probably referencing the cheesy movie, in fact the cardboard chute did catch on fire and create a startling fire outside the kiln. One of the students rushed to get a watering can and put out the fire.