The 74th annual junior inter-county got under way early on Saturday morning at the Clickimin running track.
With a vociferous home backing Shetland started with a bang, with Murray Todd winning the boys 800m race.
But Orkney responded to win the girls 800m and boys long jump events.
The hockey will follow at the Brae pitch at 4.15pm before the football starts at the Gilbertson Park at 7.15pm.
The Stuart Cup action culminates with swimming and netball, both at the Clickimin, tomorrow.