Tokyo - Rugby World Cup officials said they would inspect venues for Sunday's matches immediately after Typhoon Hagibis has passed before deciding whether they can go ahead, as the crunch Japan-Scotland game in Yokohama hangs in the balance.
As one of the most powerful storms in decades swirls towards Japan, governing body World Rugby said on Saturday: "Our primary consideration is the safety of everyone.
"We will undertake detailed venue inspections as soon as practically possible after the typhoon has passed and an update will be published as soon as that process has been undertaken in the morning," the statement added.
World Rugby has already axed two matches scheduled for Saturday - New Zealand v Italy and England v France - in the first cancellations in the World Cup's 32-year history.
Four matches are slated for Sunday including Japan and Scotland's high-stakes showdown in Pool A, which remains undecided heading into the final weekend of group games.
Canada are due to play Namibia in the eastern town of Kamaishi, which was devastated in the 2011 tsunami and could still be affected by the storm on Sunday.
The USA play Tonga near Osaka, which should have seen the worst of the storm pass by Sunday. Wales face Uruguay in the country's far southwest, which is out of the path of the storm.
But the match everyone is interested in is hosts Japan against Scotland, scheduled to be played in Yokohama near Tokyo at 7:45pm (12:45 SA time).
If current forecasts are correct, Hagibis will be well into the sea east of Japan by then but organisers will need to assess any potential damage to the venue and also judge transport disruption.
The match is crucial as Japan aim to make it into their first World Cup quarter-final, which they will guarantee if they avoid defeat to the Scots.
If the match is cancelled, it will be classed as a 0-0 draw and both teams will get two points, sending Scotland home.
Even the possibility of a cancellation has sparked a row. Scotland threatened legal action if they were eliminated without playing the key match, prompting a stern response from World Rugby which stressed safety was paramount.
Hagibis has also disrupted the Japanese Grand Prix in Suzuka, where Saturday's qualifying session has been moved to race day on Sunday.
The typhoon is forecast to crash into central or eastern Japan early on Saturday evening, packing maximum gusts of 216 kilometres per hour Japan's Meteorological Agency said.
Hagibis is forecast to be the first storm rated 'very strong' to hit the nation's main island of Honshu since 1991, when Japan's category system was introduced.