KYOTO, Japan (AP) — Japanese author Haruki Murakami says his latest novel was a new experiment and grew longer than expected as he developed a desire to expand on side characters while writing.

The latest novel by one of Japan's most respected and popular novelists, "Colorless Tsukuru Tazaki and the Year of His Pilgrimage," has sold more than 1 million copies a week since it went on sale last month.

Murakami said in a rare public appearance Monday that the novel reflected his deep interest in real people and relationships rather than something implicit.

The novel is about a man who was suddenly cut off by his close friends and the process of healing from that.

Murakami's internationally known works include "Norwegian Wood" and "The Wind-Up Bird Chronicle."