Scientists have discovered that items of jian zhan or yohen tenmoku contain a unique and incredibly difficult-to-produce crystalline formation known as epsilon-phase iron oxide.
Coincidentally, the jian zhan pieces with the highest count of this formation are also some of the most coveted for their beautiful silvery appearance.
It is believed that there was no way to control the finished product in the massive wood-burning kilns in the Song Dynasty. Because the adjustment of the fire in the kilns was left to chance when the bowls were made, their final appearance was impossible to predict.
Thanks to modern technology, things are easier now.
Hayashi works with modern techniques to re-create the yohen tenmoku ware. He uses an electric kiln to get better control of firing and more consistent results.
"If I fire numerous wares in my kiln, I apply some kind of special material to one of them and (it inevitably) turns out to be a yohen tenmoku," the Japanese artisan says.
"But I want to reproduce the yohen tenmoku ceramics in 'Hayashi's style'," he says.
Now the biggest challenge for him is the weather, as different conditions can influence the flow of smoke coming out of the kiln and, as a result, the bowls.
Jian zhan or yohen tenmoku bowls are still considered among the most perfectly realized objects devoted to the beauty and culture of tea.
"It would be no exaggeration to say that yohen tenmoku ware are the epitome of the ceramic style of the world," Hayashi says.
His passion for the pottery set him on a journey of exploration that continues to this day. His long-term goal is to create a new type of yohen tenmoku.
"When I look at the replicas coming from my kiln, I always think that better ones are on the way tomorrow," says Hayashi. "I enjoy the firing process more than the wares."
