Regular RocketNews24 readers will no doubt already be aware that fast food chains in Japan like to mix things up every so often by giving their buns a splash of colour. In the past 12 months alone, we’ve seen McDonald’s present a Sakura Pink teriyaki egg burger in time for the cherry blossom, and last October Burger King rocked a Black Ninja Burger which sported charcoal-black buns and a huge tongue-like slab of bacon.