I had the Mouko Tanmen which is spiciness level 5 out of 10. It is a miso based tanmen with lots of vegetables topped with their original spicy mabo tofu. Pretty spicy, but good spicy. I sweat like half a gallon on line outside, then another half gallon eating this lol.
They have over 20 shops in the Tokyo and surrounding areas. This is a must try if you are fan of spicy food.