Update 1.6.2010: Katherine, who recently traveled through Narita Terminal 1, reports that the array of Japanese whiskies now available there is fairly impressive: "In March they were still carrying basically Hibiki and Yamazaki. This time around they had several Yoichis (12, 18 and even 20 year-olds), and the Taketsuru 21, which was selling for only ¥6000. I paid ¥10500 at Ebisu Kinokuniya in March. I also saw a Hakushu, although I don't remember the year." For more information on people's experiences at Narita, take a look at the comments on this post.
The duty free shops at Tokyo's Narita airport have a limited selection of single malts. Please remember that not all travelers will be able to rely on a last minute duty-free dive. Anyone transferring at a second airport in a jurisdiction that doesn't allow large bottles of liquids in hand luggage may find themselves trying to glug back 700ml of premium whisky at a security gate.
In August 2007, I checked two duty free shops in Terminal 1, South wing. The selection was exactly the same in both. They had 700ml bottles of 12 and 18 year old Yamazaki single malts at very reasonable prices. The 12 was at 4,500 yen compared to 7,119 yen in normal supermarkets. The 18 was 15,000 yen not 21,000 yen. The Yamazaki 12 was also available in a 180 ml bottle for 1,100 yen.
They were also selling the premium Suntory blended whisky Hibiki in 17, 21 and 30-year-old versions and a combo pack of a 180ml Yamazaki 12 and a small bottle of Hibiki 17 for 2,800 yen.
None of the smaller Japanese makers were represented and the only Nikka whisky I saw was an odd "Gold and Gold" bottle dressed up as a Samurai helmet. Incidentally, there was a lot of Scotch that is difficult to get outside Japan, including blends such as Old Parr Superior (6000 yen), at prices that were much better than the Tokyo department stores. There was also a very limited selection of shochu.
Location: Terminal 1, Narita airport, serving Tokyo.
View location on a map of single malt stores.