Right Brian. Japanese Shops seem to get rid of what is not up their inland standard for quality. In DTI, since there are charters of foreigners attending, prices are high. Best deals seem to be made about 3 weeks after DTI. Seldom do top swords reach the market, they are pre-empted before, anyway very few of us could afford them. Reason why you won't see thousands of Nagamitsu Tadayoshi, Kotetsu, ko Bizen on the market. One or two shall from time to time appear, that's all
For the wealthy ones, cheapest Juyos are Koto suriage mumei, especially in the wakizashi range.
Some less favoured schools are also cheaper, Mihara, some Yamato schools ...