Japanese convenience stores offer quite the plethora of refreshing beverage options, but Lawson's Machi Cafe seems to always have an exciting new option, such as frozen desert drinks inspired by Makoto Shinkai's Weathering with You and Hello Kitty lattes.

Now for the next month, those who bring their own tumbler when they order from Machi Cafe at Lawson can enjoy their drinks at an even bigger discount than they already do, with a new 39 yen discount.

Machi Cafe already offers a 10 yen discount on purchases for customers who bring their own tumblers, but until August 30th, customers will be given a 39 yen discount for doing the same, as part of Lawson's goal to reduce plastic waste output by 30 percent by 2030. While 39 may be sound like a random number, it's a play on the Japanese hybrid of "san" (3) and "kyuu" (9), meaning "sankyuu" or "thank you" as an expression of gratitude for helping reduce what they project to be 6.4 tons in plastic waste.

The discount is available on all sizes (except for Mega) of iced and hot coffee and lattes.