Japanese PS Plus offers an enormous total of 153 free games between modern and classic ones to its subscribers.
Within the instant collection, there are cult classics like Arc the Lad, Shin Megami Tensei, Tokyo Majin Gakuen: Ken Kaze Tobari, Lunatic Dawn Odyssey, Spectral Force, Spectral Tower II, Langrisser, Thunder Force V, Shadow Tower, Brigandine, Gun Parade March, Assault Suits Valken 2, and many more. You can see the full list here and here.
There are plenty of guides online to help you through the language barrier for most titles.
The best part of this all, is that you can play all those games for free for 15 days, thanks to a PS Plus free trial membership currently offered by Sony Japan. If you don’t know any Japanese the process may be slightly tricky, but DualShockers has given some help.
You need to create a Japanese PSN (Sony Entertainment Network) account first. The Japanese PSN often gives access to a lot of interesting stuff. There are many good guides online to do so. Kotaku has a very good one here.
Once you have your new Japanese PSN account, you can move on to grabbing the PS Plus promotion. First of all go here, and follow the instructions in the pictures below.
Congratulations! Now you’re a member of the Japanese PS Plus for fifteen days. Remember, as long as you are a member, you can re-download every single game you ever downloaded, even if you deleted it from your hard disk.
Now, you can find the games you want and download them.
That’s it. As long as the games are on your hard disk (and your membership is active) you can play them even when you’re logged on your North American or European accounts.