How a psychiatrist from Yamagata came to possess one of the world's most important collections of Japanese contemporary art — meaning art made in the last 15 years — is almost embarrassingly simple. Ryutaro Takahashi had the savings and liked the art, so he bought it. As far as the 62-year- old is concerned, that's all there is to it.

A more impartial account would note two other factors that were crucial to his success: His taste is good, and he had almost no competition. Since 1997, when Takahashi started assembling the 1,500- plus pieces that make up his collection, he was essentially the only person making regular, large-scale purchases of work by young Japanese artists.

Take Makoto Aida, for example. Christies' auction house, art historian Yuji Yamashita and former Mori Art Museum director David Elliott are just some of those who have suggested the 43-year-old is one of Japan's most important artists. Aida's "A Picture of an Air Raid on New York City (War Picture Returns)" is a giant screen-painting that tackles the country's complicated relationship with the United States through a fantastical depiction of Zero fighters that form an infinity symbol as they bomb the Big Apple. The painting was one of Takahashi's first major purchases, and since then, he's acquired "about 10" of Aida's "big paintings."