The price of the wifi-only edition of Kindle Paperwhite was shaved by 500 yen ($6.25) to 7,980 yen Wednesday, as competition heats up in a sector that has been slow off the mark.
Amazon began taking pre-orders for the gadget on October 24, with the first shipping expected on November 19.
The discount might give an edge to the US giant against a range of rivals, including the "Lideo" e-reader, with the price tag of 8,480 yen, the same as the Paperwhite before its discount.
Lideo, which is made by printing heavyweight Toppan, uses free WiMax high-speed, wireless broadband technology that allows users to connect to its BookLive ebook store with 95,000 titles, compared with Amazon's 50,000 Japanese titles.
Sony and Japanese online store Rakuten also have e-readers, while a horde of electronics makers have produced tablet computers ahead of the year-end shopping season.