Because of the manufacturing process of Hasami, even the same design has natural variations, shapes and sizes. Fine hairline cracks are considered okay but if actually damaged, should stop using immediately. The brown and black color variations are considered natural, expected, are not considered defects.
Instruction for care:
Use soft sponge
Do no use abrasive sponge
Stop using the porcelain if damaged
Some high quality Hasami is microwave and dishwasher safe
Not oven safe
Dry well after washing
Source: Hasami Porcelain by Saikai Toki Trading Inc.
