Of course you see the duty free shops in Haneda, Narita, and other airports, and many shops downtown have become tax-free recently. Drugstores and retailers have signs advertising their tax-free/duty-free status. Japanese comsumption tax is 8%, so if you visit Japan from overseas, you won't pay the tax for the item you buy in a tax-free shop. 8% can be a big difference when you buy something expensive like appliances, quality whisky and such. Just a reminder, tax-free and duty-free are different, so the discount will depend on what and where you make purchase.