Was in Narita today (Terminal 1) heading home to the US. Picked up a lot of Japan whisky while in Japan (including a Yamazaki 18 & Yamazaki Limited Edition 2015, Hibiki 17, plus other brands, Ichiro's Malt, Mars, White Oak), in department stores, liquor shops and Bic Camera. Supplies are decent for the 12 year versions, but 18 years are limited throughout Japan, but if you're persistent or lucky, you may come a store that gets a few in on the day you visit. But Narita is a major no-no if you want to get good whisky at reasonable prices. They've got 3 of the popular aged Suntory Whiskys single malts Yamazaki 18, Hakushu 18 and the blended Hibiki 17 & 30 all the "Travel Editions", in stock. The only difference between the travel editions and the regular aged editions, is the fancier bottle, with etching and box (wooden, as opposed to cardboard). It's still the same exact aged whisky. The price difference is, however, significant.

Yamazaki 18 (purchased at Bic Camera) = 24,000 Yen (no tax)
Yamazaki 18 Travel edition(at Narita Airport Duty Free) = 50,000 Yen

Hakushu 18 (purchased at Mitsukoshi) = 22,000 yen (no tax)
Hakushu 18 Travel edition (at Narita Airport Duty Free) = 50,000 Yen

Hibiki 17 (purchased at Mitsukoshi) = 12,500 yen (no tax)
Hibiki 17 Travel edition (at Narita Airport Duty Free) = 40,000 Yen
Hibiki 30 Travel edition (at Narita Airport Duty Free) = 500,000 Yen

Even other country's whisky is much cheaper outside Narita.

Johnny Walker Blue 750 ml(at Narita Airport Duty Free) = 20,000 Yen
Johnny Walker Blue 750 ml(at Japanese Super Market) = 12,900 Yen.