An onsen-style Japanese Zen bathroom centers on a sunken tub in charcoal basalt, a brushed brass spout, and a linear bed of river pebbles for tactile contrast. Warm textured plaster walls meet light cedar shoji framing a raked gravel courtyard with moss and a crimson maple. A skylight bathes the space in calm daylight, while a simple niche with an ikebana stem underscores restraint and indoor–outdoor harmony.