Yoshiko uses crystalline glazes which are one of the most difficult and challenging glazes to produce. This is because they are unusually difficult and time-consuming to formulate and fire. They require meticulous attention to the finest of detail. Yoshiko throws pots, riser rings (exactly the same diameter as the bottom of each pot) and glaze catcher dishes on a potter’s wheel. After bisque firing them, she attaches the riser ring to each pot, mixes glazes and applies them on the pieces, fires the porcelain pieces to over 2350 °F in the kiln, then quickly dropping the temperature several hundred degrees to the range where crystals will grow. The crystals form in the glaze in a chemical reaction during cooling and grow from small nuclei created during the melting process when silica and zinc come together to form zinc-silicate. Yoshiko then separates each piece from the riser ring, and grinds the bottom of each piece to smooth. Each glaze composition, together with the firing and cooling schedule, and glaze thickness, makes different forms and colors of crystals.
Ceramics have been a constant in my life and heritage. The shapes, finishes, and colors in my one-of-a-kind pieces reflect my experiences, environment, and what I find moving and beautiful. Art is found in the linkages formed between the earth, the artist, and the user through the shape and functionality of each piece. The shaping, glazing, and firing of each piece lead to endless possibilities, challenges, and new ways of self-expression as an artist.