Oni ni kanabou [鬼に金棒] is a Japanese saying which literally means giving an iron club [kanabou/金棒] to an ogre [oni/鬼], ie making something already pretty strong, pretty much invincible. It seems that during the annual festival of Setsubun on February 3, when oni run amok at kindergartens all over Japan scaring the pants off kids with only a handful of beans to protect them, the last thing you’d want to do is give them an iron club. Unless, that is, they are made of custard filled pastry and coated in chocolate.
On February 3, for one day only, you can pick up these sweet bread sets at Andersen bakery in the basement of Fukuya department store across the road from Hiroshima JR Station.
Read more about Setsubun in Hiroshima.