NHK will broadcast the May 8 Osaka International Grand Prix Track & Field Meet live from 3:05 to 5:00 p.m. Japan time. The meet features a range of international talent alongside a large number of Japanese national champions, national record holders, and Olympic medalists. Click here for complete start lists. International viewers should be able to watch the meet online for free via Keyhole TV. Click here for more details. You'll have to scroll through the channels to find the correct one, which has its name listed all in kanji and requires a password. The password is NHK.
It appears that the broadcast will begin immediately after the men's 1500 m and end just before the women's 5000 m, unfortunately.