Canadian business travelers are now able to enter Japan again, in accordance with the required procedures including 14-day self-quarantine and a visa for entry. Straight-forward business trips are not yet possible however the border has partially re-opened for those who really need to go to Japan. Further information at the links below:

https://www.mofa.go.jp/ca/cp/page25e_000337.html#ct02
(See (2) Residence Track)

https://www.mofa.go.jp/ca/cp/page22e_000925.html
(Visitors from Canada fall under the criteria of the bottom box labeled 'Other countries/regions' in 'Measures in Operation for Entry/Re-entry/Return to Japan' chart.)

If you have any questions, please contact JETRO's COVID19 Helpline: https://www.jetro.go.jp/en/invest/covid-19/helpline/