Tokyo studio International Royal Architecture designed this seaside house with the "form of a pure white arrow".

The exterior of ISM house is completely wrapped in waterproof fiberglass-reinforced polymer.

Large double doors in both sides open a tunnel through the middle of the building with rooms either side screened by sliding glass doors.

A mezzanine bridges the gap and creates an airy upper level under the roof, uninterrupted by columns.

Glazing under the eaves bounces daylight around the upper level and spills light onto the porch and yard on each side at night.

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