Are Eastern-inspired cordials the new frontier in cocktails—or a flash in the pan?Some new arrivals are making us wonder. Ty Ku is a sake-based liqueur that contains yuzu, plum, pomegranate, and ginseng; sip it over ice at Simon Kitchen & Bar (4455 Paradise Rd.; 702/ 693-4440) in Las Vegas. Qi Black Tea Liqueur, distilled from cedar-smoked Lapsang souchong tea from China’s Fujian province, has made a splash in San Francisco, where bartenders at Solstice (2801 California St.; 415/ 359-1222) mix it with bourbon, bitters, and fresh kumquats. And Soho, a lychee liqueur made from the fruit indigenous to southern China, sweetens up the lychee martini (white rum and sake) at Chicago’s Japonais (600 W. Chicago Ave.; 312/822-9600). Fine, but we draw the line at seaweed Cosmos.