Amazon.com operates in 14 countries, including the United States. It has shown its commitment to the Japanese market by making delivery services in the country available later at night than in other countries.
Rakuten, which runs e-commerce platform Rakuten Ichiba, has amplified its sense of crisis against Amazon's offensive move.
Rakuten has started a campaign to increase customer points by up to seven times the usual number if shoppers use a credit card from one of its group companies.
Yahoo Japan, which runs the Yahoo! Shopping e-commerce site, is also offering an increased points campaign to customers that pay a membership fee.
These companies are working to acquire customers, as they expect the e-commerce market to grow further.
According to the Economy, Trade and Industry Ministry, the e-commerce market, including online shopping, was worth 13.8 trillion yen ($120 billion US) in 2015.
That is almost double what the market was worth five years before.
However, there are fears that profits will come under pressure if companies go too far in strengthening delivery services and increasing points.