Found on a back street.
Spaghetti Pancho Akihabara, a spaghetti chain that specializes in large portions, will hold a 310 yen sale on March 10.
As March 10 = Meat Day, the chain will offer a plate of "meat sauce" (usually 690 yen) for 310 yen.
In addition, the restaurant will also offer a free fried egg or potato salad, and a free topping coupon for the next time you visit.