Separate tickets for flight UB-Beijing-Toronto - a side trip Beijing-Tokyo on a separate ticket

I am a Canadian citizen flying from Toronto to UB, Mongolia via Beijing. Flying back UB-Beijing-Toronto. On the way back from UB-Bejing, I want to buy a separate ticket for same day flight Beijing-Tokyo and spend 3 days in Tokyo, and then fly back Tokyo-Beijing and spend 3 days in Beijing and then resume my flight on my original ticket for Beijing-Toronto leg of the trip. Can I travel visa free?