I'm not as good as I thought with theGIMP. Create something from nothing is easier
I want your advice on this before continuing.
Here comes my idea for this map (follow it on the blue map given in the previous link):
- Mori: 13-26 = 14 territ (though I can make it 9 with the modern borders)
- Ouchi: 29-33 = 5 territ
- Ashikaga: 27, 28, 34-39, 41 = 9 territ
- Saito: 42, 42, 47, 48, 52 = 5 territ
- Imagawa: 44-46, 57 = 5 territ
- Uesugi: 49-51, 54, 50, 66-68 = 8 territ
- Takeda: 53, 55, 56 (bombards 62 from 56) = 3 territ
- Hojo: 58, 59, 61-65 = 7 territ
I would have 5 neutral territories from the beginning: 34, 63-66
This makes: 8 continents for 56 (or 51) territories.
In fact, there are castles everywhere, so I can't follow the idea of bonuses on castle territories. Mountains are also almost everywhere, therefore I can't add impassable mountains or even rivers. But Japan is quite linear , so the shape of the territ will do for the impassable ways.

OK, OK, I'm doing a rough map for now. Thus we'll see if we can see the smallest territories.