If you happen to be in Tokyo between April 3d and April 5th and have some spare time, you should check out Art Fair Tokyo 2009.  Most of the exhibits are more focused on contemporary art, but there are four booths that I think you should visit that are antique based.  I will quickly list the vendors of interest and briefly describe what you will see.

Shouun Oriental Art: Booth D11.  Artworks from the Jomon to Edo era.  This should be super cool.

Mita Arts Gallery: Booth E06.  Woodblock prints from the Edo to Meiji era.

Gallery Kono: Booth D01.  Early Imari and Kakiemon Porcelain as well as examples of Maki-e lacquer.

Tannaka: Booth D13.  Pottery from the Kamakura and Muromachi eras; Tamba-yaki, Tokoname-yaki, Shigaraki-yaki.  As well as Noh artifacts; costumes, masks, and instruments.

There might be other exhibitors showing antiques, but these were the ones I found as I went through the exhibitor list which is extensive.  Many have links to their home pages, so feel free to peruse them to see if anything else piques your interest (click here).  You’ve got 2 weeks to book your flight, so check your calender, it looks like a huge exhibit not to be missed.