Ghibli Tickets, when start to sell?

Hi,
When exactly can you start buy tickets for the Ghibli Museum?

They say it can be reserved 1 or if it is 3 months ahead, at least through travel agencies.

So if I want to reserve a ticket in Japan on November 1st, when can I reserve it from?

And same goes with the agency....

For tickets bought from Lawson:

From the 10th of each month, they start selling the tickets for the following month. Which mean, November tickets will go on sale on October 10th (the following weekday if the 10th falls on the weekend).

Considering school holidays, the rules seem to be different for July and August tickets, though.

For travel agency sales, you would need to ask the agency.

I won't go into detail about how to purchase tickets whilst in Japan as the above poster has already covered that.

But if you want to purchase your tickets from overseas, JTB will be your best bet. You can purchase the tickets 3 months in advance so you if you wanted to (and I'd advise it), you can purchase the tickets from the start of August according to the JTB page.
More information (including links to the agencies of your respected countries) can be found here on the official Ghibli Museum page. http://www.ghibli-museum.jp/en/ticket-information/

I purchased my tickets with JTB and it was hassle free. After purchasing them online I received my tickets in the post. Make sure you don't lose your confirmation slip though as they won't send out another one and the museum won't admit you without it!

And if somehow you live in the UK http://www.japanspecialist.co.uk/ghibli-museum/ticket-only/