When it comes to Penghu’s basalt landscapes, it’s impossible to overlook Jishanyu. Many call Jishanyu "Huangshan Mountain in the East China Sea," likening it to a famous scenic area in China. Located four kilometers northeast of Beiliao Village in Huxi Township, Jishanyu comprises two islets, Big and Little Jishanyu. When the tide is out, you can cross from one to the other on foot.

Both Big Jishanyu and Little Jishanyu are basalt mesas; the columnar joints on the surrounding sea cliffs are clear and distinct. Sea trenches and caves surround Big Jishanyu, and there’s a shoal off its southeast shore. Little Jishanyu’s tightly arrayed hexagonal basalt columns look like a pipe organ; hence, its English name is Organ Island. Much of the basalt here contains green olivine. Olivine has a very high melting point; the mineral is brought up from deep underground when basalt magma rises to the surface. Jishanyu is a listed basalt nature reserve; and permits are required to land on the isle. Apply beforehand.

Like Dinggouyu, Jishanyu yields an abundance of edible seaweed in the winter. The nearby villages of Guoye, Nanliao, and Hongluo Sanshe villages have been taking turns harvesting the crop since Qing Dynasty times. It’s the villages’ chief source of income–– and that’s why they call it "black gold”!

Jishanyu is a breeding ground for terns in the spring and summer, mainly crested terns. But even rare black-billed crested terns, the so-called "mythical birds," have been sighted here. Cruise by and check them out––Jishanyu is a birdwatchers’ paradise!