"It's one of those unique, trophy-hunter bottles that is so limited," said Jonny Fowle, global head of spirits at Sotheby's. The Kodawari -- which means "art of perfection" -- collection also includes bottles from well-known distilleries like Hanyu, Yamazaki, and Hakushu. Suntory Group owns the Yamazaki and Hakushu distilleries. The collection is expected to fetch 1.6 million to 2.1 million pounds in total, making it the most valuable set of Japanese whiskies ever to be auctioned, according to Sotheby's. The high value is testament to the rising popularity of Japanese whisky, which has leapfrogged U.S. and Irish ones to become the second most sought-after by collectors, behind only Scotch. The anonymous collector behind Kodawari is still only selling around 20% of his collection through the auction series at Sotheby's, speaking to the amount he has accumulated in the two decades since falling in love with a Karuizawa whisky in Paris.