Forced Bridge

Medium Used by Smart Hint

Even maxing out every other connection would leave this island short — so this connection must carry the difference.

Bridge to add
Islands that establish the pattern

How it works

The corner island needs 3 bridges across two directions.
If either direction carried nothing, the other could supply at most 2 — one short.
So each direction must carry at least one bridge. The same logic applies to a 5 on an edge or a 7 anywhere.