It could get even tougher.
Argentina will get drawn alongside one of defending champion New Zealand, England, Australia and Ireland from the band of first seeds, and one of Scotland, France, South Africa and Wales in the band of second seeds.
It leaves open the possibility that three countries from the southern hemisphere's Rugby Championship could be drawn in the same pool, with either New Zealand or Australia potentially in with South Africa and Argentina.
Japan, the first host nation from Asia, is among the third seeds and also faces getting picked in a tough group.
Twelve countries have qualified directly for Wednesday's draw, courtesy of finishing in the top three in their pools at the 2015 Rugby World Cup. The other eight countries will come through global qualifying, which started last year.
The draw takes place 2½ years ahead of the Rugby World Cup to allow organizers time to sort out the match schedule and ticketing, confirm venues and arrange base camps. The tournament runs from Sept. 20-Nov. 2, 2019.
"It is the first time that the pool draw has been hosted outside of the UK or Ireland," said Akira Shimazu, chief executive of Japan's organizing committee, "and we are determined to make the most of this opportunity to showcase the very best of Japan to the world, and the best of rugby to Japan."
Band 1
New Zealand (1), England (2), Australia (3), Ireland (4)
Band 2
Scotland (5), France (6), South Africa (7), Wales (8)
Band 3
Argentina (9), Japan (11), Georgia (12), Italy (15)