Blue corner
Blue corner is sometimes visual event on canvas in which a corner gets a square or rectangle of blue. Then upon it, written Blue corner or something to that effect.
Blue corner existed from the start of r/place and was able to take most of the map in the first event.
There was one the reddit place canvas in 2022.
Unlike a void, Blue corner takes over usually rectangular area in the corner but then stops and will often negoatiate agreements with nearby areas to secure enough area for blue corner in a peaceable way.