Prices at discount stores double or more as cost pressures become critical issue ahead of upper house elections next month

There can’t be a household in Japan that doesn’t own a few items from a 100-yen shop – anything from chopsticks and teacups to air freshener and bin bags.

But the wildly popular discount stores – whose roots lie in the country’s long battle with deflation – are having to compromise on their USP, as soaring raw material costs, the war in Ukraine and a weak yen force companies to raise prices.