Here in Belgium they said: Next year January - February. The official documents say February, so I guess they are not obliged to do anything before then.
If my gut feeling (based on the things I read online and heard through different channels) is correct the confirmations will usually be sent to the various embassies between Christmas and New Year. This means that if you live in a country where that is a holiday period, you will have to wait until at least the beginning of January.
Disregarding this guess, it could also be that it depends on the amount/quality of candidates in your country. If the documents are only posted to your country when all applicants from your country are screened, the moment of reply can fluctuate a lot. If your country has a lot of applicants, it can also take a while before the documents are processed at your local embassy, since it would be fair to contact everyone from a particular country at the same time.
From our perspective it is of course a long wait, but I can imagine that the people at the Japanese ministry of education are trying their best to solve the enormous task of screening all the thousands of applications, of finding places for those people who have not managed to get a university of preference, of deciding who of the given applicants can go to their first university of preference and who should be replaced in case a certain university department or dormitory has too many international students.
I think however that for most of us, the waiting is especially hard, because we do not know yet, if we are (100%) selected to go to Japan or not. Personally, I wouldn't mind waiting a couple of extra months for the decision to which university I would go to, but I do feel a little bit unease about the wait prior to knowing if I can afford to study in Japan next year or not. (I would imagine that none of us can afford the tuition fees and living expenses without this scholarship)
I am not planning to contact my embassy before the year ends, because as far as I know, they didn't make me believe that I will receive an answer prior to New Year. I can imagine that this lies differently in other countries; however bear in mind that in case the people from the local embassy are also still waiting for the documents, they can not do anything. Either the documents will be there or they will not be and the embassy will not know when they will arrive.