If you look at Japan's 2020 political calendar now, it will look like it is going to be a relatively quiet one.

The one event looming large on the horizon is the 2020 Tokyo Olympics and Paralympics. With the global spectacle taking center stage, it's not hard to imagine that Prime Minister Shinzo Abe and the ruling bloc will be focusing all their efforts on hosting the event successfully and avoiding any politically contentious issues during that time.

But with the games set to start in late July, that still leaves six months of the ordinary Diet session, which will start in mid- to late-January and close in June, open to political wrangling.