One of the most essential elements in creating the beautiful hues of Hagi ware is the clay itself. Because Hagi ware is traditionally left undecorated, its final coloration is greatly influenced by the type of clay used. Even when the same glaze is applied, the outcome can vary significantly depending on the clay body.

At Chinshu Kiln, clay is blended using a machine known as a dorenki (clay kneader). The composition is adjusted for each product to bring out its intended character. While this process can be time-consuming and result in material loss, it is a vital step in ensuring color consistency and overall quality.

The primary materials used are traditional clays long associated with Hagi ware—Daido clay, Mishima clay, and Kinpo clay. These are blended in-house, with fine adjustments made to their hardness and proportions to create the ideal base clay for each piece, depending on the desired color and texture.

In this way, Chinshu Kiln approaches each piece with great care, starting from the clay itself, and strives to find the most suitable combination of materials and finish to express the character of each work.

In generally Hagi ware, two types of glaze are commonly used: dohai-yu (transparent ash glaze) and warabai-yu (white straw ash glaze).

However, at Chinshu Kiln, artisans are pushing boundaries by experimenting not only with these traditional glazes but also with colors previously unseen in Hagi ware—such as blue and green. The glaze preparation area is filled with barrels of various sizes, tightly packed together. At the heart of this pursuit lies the passion of artisans who are constantly seeking new colors for the future.

In the glazing process, artisans carefully apply the water-diluted glaze by hand, one piece at a time. Weather conditions, temperature, and even how the kiln is packed influence the density and composition of the glaze, requiring fine-tuned adjustments throughout the process. The liquid glaze is kept constantly stirred to maintain uniformity, and is applied with great precision and care.

The way the glaze melts and overlaps can significantly affect the final color after firing. Even when using the same clay and glaze, the finished piece can take on a completely different appearance.

For example, a piece that appears purple may not use any purple glaze at all. Instead, red-toned clay is coated with white glaze, and depending on the kiln atmosphere and firing temperature, the final color may shift toward bluish or reddish tones.

For this reason, each piece from Choshugama can be considered one of a kind, shaped by the unique balance of glaze, clay, and firing.