Traveler's checks? In Euro or Yen?

In yen so you wouldn't have to exchange again when in Japan. But t/c are rarely used in Japan as you note it is a cash society. And I son't think many places other than the large hotels and big stores would take them. Lots of places will take cc though like hotels,ryokans, stores, gas stations and restaurants in larger cities. See here for exchange rates as all Japan banks will be about the same....

http://www.narita-airport.or.jp/exchange_e/index.html

I think now the t/c companies now can set you up with a debit card situation so you don't even have to use the t/c's anymore. I have only seen commercials of this and have never really checked it our but you should if you are planning to use your finances in this way.
Aloha!

I am not a regular traveler to Japan but when I do travel there I carry about 50,000 Yen in cash and make do with credit cards and ATM.

Why would you think carrying Euros in Japan is beneficial?
Why withdraw money from your credit card? Don't you get charge like 3% for cash withdraw and then compound that with exchange charges?
Why such little withdraw limits? 200 Euro per week is nothing!

I don't intend to use TC's directly to pay for purchases, but rather exchange them for cash at banks that support them.

I'm a bit concerned about carrying €1.500 in cash with me

Trying to exchange travelers cheques in japan is a huge pain. You would dfinitely wan to have them in yen, and even so you will probably wait ages while they disappear behind closed doors and do goodness knows what.

As a poster stated above, have cash - stashed in more than one secure location and use an ATM card - post office and Citibank ATMs work, some others. Lots of places, large department stores, hotels etc do take Visa and Mastercard so you should have no need to use TCs. In fact, I have a couple that have done two trips to Japan and never got the chance to cash them.

I'm not sure I quite understand about the 200 euros a week limit on some sort of withdrawal. Do you mean your bank only lets you withdraw the equivalent of 200 euros a week from ATMs using your bank ATM card? That is extremely low--most banks allow more like 200 euros a day.

Anyway, I found that lot of places do take credit cards, though not as many as in Europe and the USA/Canada.

And for cash, ATMs are easy to find (7-11 stores and the post offices do not have additional transaction charges for using their ATMs). Though if your bank does impose a 200 euro per week limit on you for some reason that is a problem.

Yes, the MasterCard and Visa cards I have are basic (no need for more when I'm home) and will only allow cashing out €200/week.

I even got my card blocked by either Visa or the network they rely on while travelling in the US. It's a bit of a pain to have to call home collect to have the parents wire some money because you trusted plastic

Hence the need to carry money in a different form.

Thanks everyone.

And you can't ask them to raise your limit while travelling? They'll usually do that for a specific period of time.