No offense intended, but I did some research and found out, this RP can't possibly play in 1212. It has to play somewhere in the 1400's, more likely 1450+ and I have some very good reasons for that. (Not all are listed, I could go on and on)

1. Katanas were first made in the era of the Ashikaga Shogunate, more accurately, somewhere around 1400 and 1420.
2. Samurai, before the Sengoku period, which starts with the Ounin war 1467, were the only real warriors in Japan. After that, Samurai became increasingly rare and somewhat of an elite soldier, training for all his life. Normal "soldiers" were the ashigaru, then. Also, before the Sengoku era, you were born a samurai. One couldn't become one in battles.
3. The first Ninjas were trained in the 15th century, so somewhere 1400-1500
4. Most Rounin were nothing but petty bandits before the Sengoku era, when the daimyos suddenly needed excellent warriors.

I hope, I haven't offended you with this and you can see my logic in here. Not that it would really change anything, it'll just make the background reasonable and logical.
(Yes, I am a big, big, big history nerd)

EDIT: By the way, anything until the Meji restauration 1868 is officially called feudal Japan. You could go with an alternative deadline, the start of the Edo period 1603.