2, the pattern is clear, emphasizing the symmetry of the pattern layout.
3. Observing with a magnifying glass, we can see that there are fresh and bright bubbles with different sizes and uniform distribution in the glaze.
4. Black glaze in Song Dynasty is a kind of porcelain products, which is often called "Wu", "Black Sword" or "Purple Sword" in ancient books and "Tianmu Porcelain" in Japan. Burning began at the end of the Five Dynasties and the beginning of the Northern Song Dynasty, and the peak period was the Southern Song Dynasty. Black glazed porcelain can be divided into blue-black glaze, gray-black glaze and gray-white glaze.