Throngs of eager Japanese readers are rushing to buy celebrated writer Haruki Murakami's latest novel, despite knowing almost nothing about the new book.

The mysteriously titled Colourless Tsukuru Tazaki and the Year of His Pilgrimage officially went on sale in Japan Friday, with flocks of Murakami devotees queuing outside bookstores overnight to be the first to get their hands on the novel at midnight.

The fans were buying on Murakami's reputation alone, as the publisher released few details besides the title of the novel in advance of its sale.

"We did not want to give any preconceptions to the reader," Tomoya Tanimura, of Murakami's publisher Bungeishunju, said of the secrecy surrounding the book's release.

Though Bungeishunju set up a special online site for the novel, it lists little more than the title and Murakami as the author. The publisher also had doled out tidbits of info since mid-February.

"I started out writing a short story, but as I was working on it, it got longer naturally. I've rarely experienced this...maybe not since Norwegian Wood," Murakami said in a statement.

A first printing of approximately 500,000 copies was shipped to bookstores in special cardboard boxes to prevent leaked images of the book cover ahead of Friday's release. Murakami's first book in three years, Colourless Tsukuru Tazaki and the Year of His Pilgrimage was pre-ordered by 20,000, according to online retailer Amazon.

The publication date for the English translation has yet to be announced.

Hungry fanbase

Fans and book reviewers in Japan raced to finish the novel straight away, according to media reports.

"I cannot sleep tonight at least until I finish reading this book," Kazuki Yamashita, 20, told a Japanese TV channel.

Bookstore clerk Michiko Mamuro, 52, read the novel in two hours and told Japan's Asahi Shimbun newspaper that the story is set against the massive earthquake and subsequent tsunami that rocked the nation in 2011. 

"The book has strong messages and many encouraging words," Mamuro said.

The new novel follows Murakami's mind-bending, widely acclaimed three-part epic 1Q84, in which the lives of a murderer and an aspiring writer become intertwined. The complex work was an instant bestseller in Japan and, later, a hit internationally in translation.

Often touted as a nominee for the Nobel Prize, Murakami is known for penning surreal tales that play with reality and perception, tackle issues of alienation and isolation, and are infused with humour and modern references, including much contemporary and classical music. His works include Hear the Wind Sing, The Wind-Up Bird Chronicle and Kafka on the Shore.

He is also a noted translator of American fiction and has penned short fiction and non-fiction as well. Although celebrated, Murakami keeps a low profile compounding his mystique.