TRAVELING TO JAPAN! Recommendations for shops for cartridges?

The single best store for choosing among many many different cartridges that are all "in stock" and ready for immediate sale is Yodibashi Camera, which is located in the Akihabara section of Tokyo.  Brands include Audio Technica, Grado, Ortofon, Shelter, Ikeda, and now my mind is going blank but there are more. Go to the 4th or 5th floor of the enormous building, as big as Macy's in NYC, and you will see a myriad of cartridges, as well as all other imaginable audio accessories and basic equipment.  There are even 2-3 different listening rooms where you can mix and match components you might want to hear.  Akihabara is a major train stop for many different lines; you almost cannot miss it.  And Yodi is right outside one of the main gates of the massive train station.  For LPs, I would go to Disc Union, which is near the Ochanomizu train station, one stop away from Akihabara on one of the train lines. (Maps in English are all over the place in train stations.)  Across the street from DU is a boutique audio salon, Audio Union, part of the same business, if you want to look at gear in a very quiet setting.  Yodibashi is a bit unique in that they will discount the Japanese tax beforehand, if you present your passport, whereas if you do business elsewhere, you have to pay the tax and then get a refund at customs (or so I am told).

I preferred the MP-200 over the 500 in my system, either are wonderful cartridges and I am sure they could be acquired for a reasonable sum in Japan vs US. 

There you go; Yodibashi sells Nagaoka, too.  In fact, I bought an MP500 there in May for about 60% of US price.  Don't know why I forgot Nagaoka in my post above. The bargain price is mostly because of the very favorable exchange rate, yen to dollar, that still prevails, not because of a greedy importer.

Thank you @knotscott @lewm @jeffrey125 for the recommendations!

it is also necessary to evaluate the price ratio in the country of origin/and price in the country of residence.
When years ago I went to the USA for some time I had brought with me a list of cartridges with the costs in my country; arrived in N.Y. I inquired about the costs at a large and well-known shop in the city.
I bought some top-of-the-range Grado for me and some friends and a Krell, the cost was about 7 times lower than in my country, the savings were considerable; it would not have made sense to buy European or Japanese cartridges in the USA.
If you go to Japan, the savings are on Japanese-made cartridges, not imported American or European brands.