Soft cola flavoured gum balls with a gooey cola paste centre. The bubble gum balls come nestled in a small plastic tray. Watch out! One of the three tasty bubble gum treats is actually a super sour flavour sweet in disguise. Try your luck! Bubble gum is a popular sweet in Japan and comes in all kinds of flavours, types and styles. The 1st of July has been designated Gum and Chewing Gum Day in Japan, but we won’t blame you if you can’t wait ’til then to tuck in.