Record Shopping in Tokyo

I've been fortunate to visit Tokyo several times, and the music shopping I've had time for was mainly spent at various Disk Unions and Tower Records buying classical CDs. I'm setting aside a few days for vinyl shopping on my next trip, and I'd be grateful for recommendations, including out of the way stores. My interest is specifically used 1960s-1980s rock.

Next question is what I should expect to find, in the way of Japanese, UK, etc. pressings, what to generally look for and what to avoid. I'm aware that some Japanese pressings aren't great because second generation tapes were used, but what should be sought out? The exchange rate is bad right now but that just means I'll buy 20% fewer albums (or not).

Domo arigato.