Place · in Nantou
Yuchi (Sun Moon Lake)
Yuchi is the township wrapped around Sun Moon Lake, and it is the one part of Taiwan built on large-leaf assamica rather than on the small-leaf Chinese bushes behind the island's oolong. It is a black tea place by design rather than by tradition: the plantings began as a colonial project, the cultivars come out of a research station still working in the township and the modern industry was rebuilt from very little after the 1999 earthquake.
What grows here
Black tea, and in commercial terms only black tea, sold as Ri Yue Tan hong cha (Sun Moon Lake red tea). Small quantities of oolong and of bug-bitten summer leaf are made in the township too, but the lake name means hong cha to anyone buying it. The oolong hills that made Nantou's reputation start a short drive away and have nothing to do with this.
The ground
The lake sits at about 750 m in a basin ringed by hills, and the elevation is deliberately mid-range: high enough to be worth planting, low enough that the assamica bushes get the heat they want. What a body of water that size adds is humidity and a narrower day-to-night swing, the opposite of what a high mountain oolong garden is chosen for. Summer rain that would spoil an oolong flush anywhere else on the island is what this crop is grown for.
The bushes
This is the one Taiwanese origin where the cultivar changes the tea completely, so it is the first question to ask. Taiwan Ruby #18 (Hong Yu) is the flagship, a cross of Burmese assamica with the island's native wild tea, and its cooling menthol and cinnamon aroma is genetic rather than added. Hong Yun is another numbered release grown alongside it. Older Assam selections descended from the Japanese-era seed are still worked and drink like a soft Assam rather than like Ruby. Shan cha, the native mountain tea itself, is made in small quantities in its own right.
Harvest seasons
Summer is the good season, which inverts the rest of Taiwanese tea, and picking runs across a long stretch of it rather than in the two tight windows the mountain gardens work to. Nobody is bidding on a winter lot here. So if a Sun Moon Lake black tea is being sold to you on a spring or winter harvest date, the date is not the recommendation the seller thinks it is.
What to look for
Ask for the cultivar, not the lake. Sun Moon Lake is a tourist destination first and a tea township second, and township output is small against how well the name sells, so a great deal of black tea from elsewhere in Taiwan carries it. Ruby #18 is now grown across the island and honestly labelled as a cultivar wherever it is, so a Ruby from another county is not a fake, while an unspecified Sun Moon Lake black tells you nothing at all. The specific adulteration to expect is cheaper black tea blended in to stretch the Ruby aroma.
How it got here
The Japanese administration brought Assam seed from India to Yuchi in the 1920s, looking for a black tea it could sell into Europe without competing with Japanese green, and set up a research station in the township to work on it. That station is still where the cultivars come from. Production fell away after the war as the export markets went and the island turned to oolong, and the revival is recent: the 1999 earthquake, centred in this county, wrecked the area, and the rebuilding pushed Yuchi back toward black tea with Ruby #18 as the cultivar to rebuild around.