Hakatamangetsu (博多満月 市ヶ谷店) provides only ¥500 lunch buffet.
When you go there, you will order one main meal and pay ¥500.
After that you will pick up many food such a udon noodle,japanese curry and rice.
It is self style buffet.
Ichigaya is quit close to Shinjyuku.
If you go there dinner time, you can drink beer only ¥199 and eat yakitori from ¥46.
Yakitori – Wikipedia
They only provide a japanese lunch menu so please use a google translate app for translation.
japanese lunch menu
Google Translate for android
Google Translate on the App Store
●Shop name: Hakatamangetsu (博多満月 市ヶ谷店)
URL:Hakatamangetsu – Ichigaya/Motsu Nabe (Offel Hot Pot) [Tabelog]
Station: Ichigaya
Ichigaya Station – Wikipedia
Lunch time : from 11：30 to 14：30（Last Order:14：00）