Final answer:
Kamakura-period portraits of Zen Buddhist masters served as aids for meditation, expressions of enlightenment, and instructional tools for students, utilizing ink wash techniques to convey spiritual depth.
Step-by-step explanation:
Kamakura-period portraits of Zen Buddhist masters serve a multifaceted purpose. During the Kamakura period, the portraits of Zen masters were not merely artistic representations but were imbued with deep spiritual significance. They functioned as aids for meditation, as expressions of the enlightened state of the masters, and as an instructional tool for students of Zen. The ink wash technique used in these portraits, later seen in the Muromachi period and carried on by artists like Toyō, utilized varying strokes and gradations of ink to convey spiritual depth and the Zen emphasis on simplicity and insight. Through these portraits, the insights and achievements of the masters continued to inspire and instruct subsequent generations, serving as a bridge between the physical and the spiritual worlds.