A novel published in 2001 depicting the love between two teenagers became the all-time best-selling novel by a Japanese author Friday, with 2.51 million copies sold.

The most recent work by Kyoichi Katayama, "Sekai No Chushin De, Ai Wo Sakebu" ("Cry Out for Love at the Heart of the World"), published by Shogakukan Inc., surpassed the previous record set by "Norway No Mori" ("Norwegian Wood"), by Haruki Murakami.

Katayama's work, published in April 2001, is about two high school students, Sakutaro and Aki, who are separated when Aki dies of leukemia.

Research Institute for Publications said "Norwegian Wood," published by Kodansha Ltd. in September 1987, had sold 2.38 million copies.

Katayama said he does not know why his book is selling so well.

His book has been made into a film of the same title.