A few years ago, McDonald's Japan debuted a special evening menu called Yoru Mac (Night Mac). Available after 5:00pm, the menu you allows you to double the existing amount of patties on any standard burger on the menu for an extra 100 yen--it's also the only time you can grab one of their savory rice burgers.

It seems McDonald's Japan noticed that not many people knew about another way to get some extra goodies at a discount, taking to their Twitter account to announce that "this isn't well known, but at nighttime only, French fry and McNugget sets are cheaper."

McDonald's is referring to their popular PoteNage (called the "Potenage" as French Fries are called "Fried Potatoes" in Japan) Sets, a combo of French fries and Chicken McNuggets as a set meal. Customers can order a Large (1 large fries and 10 piece nugget set for 730 yen) or a Special Large (2 large fries and 15 piece nugget set for 1,250 yen). However, on the Yoru Mac Menu, a Large is reduced to 500 yen and a Special Large is marked down to 800 yen. While it's quite a bit of food, at 30% cheaper than usual, it's a pretty filling meal for friends and family.

It looks like McDonald's estimation might be right, as many commented on the post saying that while they had ordered from the Yoru Mac menu so often, they hadn't noticed the cheaper PoteNage sets. Now that the knowledge is even more out there, it's a chance to try out the many seasonal McNugget dipping sauces of Japan.