Nestled at the foot of Mt. Mochomu in Yakushima, a former gazebo has been transformed into a serene tiny house, embodying the essence of a Zen retreat. The site, stretching vertically from mountain to sea, has been redesigned as a space where wind and water flow freely, allowing the surrounding forest to breathe in harmony. A second, larger roof has been added atop the original structure, creating deep eaves and a ventilation layer between the roofs. This natural airflow, from the walls to the roof, ensures a cool and comfortable interior even during Yakushima’s humid summers. The elevated flooring, another thoughtful feature, prevents moisture buildup, maintaining a dry, healthy living space. The cedar exterior walls, treated with persimmon tannin, enhance weather resistance while blending seamlessly with the natural surroundings. The renovation prioritizes the use of local Yakushima materials. All the wood comes from Yakushima cedar, and the earthen walls are crafted from local soil mixed with plaster. These materials provide excellent moisture absorption, ensuring comfort even in the island’s humid climate. For insulation, solid 60mm cedar boards, also sourced locally, line the walls as heat storage elements, while smoked charcoal made from rice husks is used to insulate the attic and flooring. Inside, a large single pane of glass frames the surrounding garden and forest, turning nature into a living landscape. Locally sourced cedar is used throughout the interior—for the floors, walls, ceiling, furniture, and fittings—offering warmth and unity. The kitchen and storage opening, intentionally low, creates the effect of a framed landscape painting. Ventilation doors in the walls allow precise control of light and airflow, while gray tiles in the kitchen and entryway are crafted using traditional Japanese smoked silver tile techniques. This tiny house, a harmonious Nest in the forest, lives and breathes with its environment, offering a tranquil escape that merges architecture with nature.