A large typhoon is currently travelling over the Pacific Ocean and could potentially affect two major sporting events this weekend.
It is expected to bring heavy rain and strong winds, and has the potential to cause damage to buildings and homes.
BBC weather presenter Simon King says October is in Japan's typhoon season, so the typhoon "won't come as a great surprise".
Although its exact route is still uncertain, it is now expected to hit further north, on the island of Honshu.
The typhoon is very large which means the effects are expected to be felt hundreds of miles away.
Japan's Meteorological Agency (JMA) says Typhoon Hagibis "could be the strongest to hit Japan this year".
It is one of the most powerful tropical cyclones this year joining the likes of hurricane Dorian and Lorenzo.
World Rugby says it has a plan in place should the weather impact the tournament.
If any games are cancelled, they will be recorded as 0-0 draws.