Any good deal Japanese buffet ?

I will be traveling for a full 27 days in Japan on quite a tight budget and I am not a big eater or fan of Japanese food; so I can expect to lose weight or even starve in some days. So once in every few days if possible, I will like to have a buffet to make it up but do not wish to spend too much as most of my budget already went into the transport(which is so expensive even with a train pass) and lodgings.
Is there any budget Japanese buffet anywhere that you may know of ? It need not be an outstanding place or great food as long as it is Japanese and cheap.

I can't give recommendations for any particular buffet restaurants, but if you don't get any personal recommendations, you can try going to www.bento.com, selecting the city you'll be staying from across the top, selecting special features down the left (under the heading restaurant listings), and selecting buffets- all you can eat.

From looking at the listings for Tokyo, there are a few cheap Japanese buffets, but most of the buffets seem to be expensive or non-Japanese. Some of the Japanese places listed there are also tabehoudai, which differ from buffets by being made to order, and charged per time slot (normally 90 minutes). They could be out of your budget if you decide to stay longer.