Green Island, known in Mandarin as Lǜdǎo (綠島) and in the local indigenous language as Sanasai, is a volcanic island roughly 15 square kilometers in area. Its geology is the key to Zhaori's character: magma beneath the island heats both seawater infiltrating through the rock and groundwater from below, producing the mineral-rich, slightly saline water that surfaces at the spring site on the southeastern coast.

The temperature range — 60 to 70 degrees Celsius at the source — places Zhaori firmly in the category of high-temperature springs, the kind where you can watch steam lift off the surface at dawn. The salinity is mild compared to ocean water but distinctive enough to give the water a soft, slightly slippery quality against the skin that freshwater springs lack. The facility includes three open-air pools, a spa pool, and five terrace-like soaking basins stepped down toward the water's edge.

During the Japanese colonial period, when Taiwan was under Japanese rule from 1895 to 1945, the spring was called Asahi Hot Spring — asahi (朝日) meaning 'morning sun' in Japanese, a name that suited the spring's eastern exposure and the way the first light of day reaches the pools before anything else on the island. The current name, Zhaori, is the Mandarin rendering of the same meaning: zhāo (朝) for 'morning' and rì (日) for 'sun.'

The continuity of the name across two languages hints at the spring's enduring character. Whether arriving at dawn to catch the sunrise from the pools, or at night to soak beneath stars with the sound of the surf close by, Zhaori has been drawing visitors for a very long time — long enough that the Japanese administration found it worth naming.

The appeal of Zhaori is sensory and immediate. The pools sit at the coast's edge, close enough to the sea that the sound of breaking waves is a constant presence. Sunrise from the pools faces east over open Pacific water — on clear mornings, the light arrives in long horizontal bands across the ocean surface before it reaches anything else. At night, the pools offer darkness and salt air and the sound of the surf, with minimal light pollution on Green Island's less-developed eastern shore.

Green Island is reached by ferry from Fugang Harbor south of Taitung (about 50 minutes on a fast ferry), or by small aircraft from Taitung Airport (RCFN, flight approximately 15 minutes). Most visitors base themselves in one of the island's small guesthouses and circle the island by scooter or bicycle on the 17-kilometer coastal road. Zhaori is on the southeastern section of that circuit, typically visited in the early morning or late evening to make the most of the light and the relative quiet of those hours.