South Korean leadership elections are held every five years. Japanese ones come around about every five minutes. This month, the two arch rivals – Asia’s second and fourth-largest economies – will pick a new leader within three days of each other.

Japan has had so many prime ministers in recent years that almost everyone you can think of has already had a go. Shinzo Abe, who had a brief turn in 2006 – since when no fewer than five prime ministers have served – is very likely to get a second bite at the cherry. His election would mean a lurch to the right of a Japan increasingly fearful of a rising China. It would also mean the comeback of the Liberal Democratic party after a three-year absence.

South Koreans, meanwhile, must choose between Park Geun-hye on the right and Moon Jae-in on the left. The two are running neck and neck following the withdrawal of independent candidate Ahn Cheol-soo, a popular software entrepreneur who pulled out last month to the dismay of many young voters who had been invigorated by his unconventional campaign.