Former Australia and Saracens coach Eddie Jones has been admitted to hospital in Tokyo because of illness.
The 53-year-old is head coach of the Japan national team and had been preparing his players to face world champions New Zealand on 2 November.
A spokeswoman for the Japan Rugby Football Union told news agency AFP he has shown signs of a minor stroke.
Jones took over from All Black John Kirwan as Japan head coach in April 2012 and enjoyed a win over Wales.
"He was with the team's staff at the time and they went together to a hospital in Tokyo by taxi," Mayuko Watanabe told AFP.
"The doctors said he was showing signs of a light cerebral infarction and he was hospitalised for examination."
After taking on the All Blacks, Japan are due to travel to Europe for matches with Scotland on 9 November, Gloucester three days later, then Russia in Colwyn Bay and finally Spain in Madrid on 23 November.