I've mentioned before the play on words that make Kit Kats a popular item to give students around exam time. Kitto katsu in Japanese translates to surely you will win. So a gokaku mug or pentagon shaped mug is a fitting promotion. Gokaku is a play on words that translates to luck. Since it's exam time here in Japan for stressed out junior high school students trying to get into a good high school as well as stressed out high school kids trying to get into a good college a good luck mug with a packet of Nescafe Cafe Au Lait and a Kit Kat bar makes for a nice encouraging gift.
If I didn't have around 400 students getting ready to graduate and move up to high school then I might buy them all one. Instead I will sit in my apartment, sipping Nescafe, and thanking God I'm no longer in school.