Counter-wardingCounter-wards are relatively straightforward - you place the wards of revelation where the enemy has placed wards of sight.
However, sometimes you don't know where the enemy has warded, though you do know they have wards, and so it's best to cover multiple areas, as shown here:

This location will allow you to counter the two locations to the northwest and southeast of the placed ward.

This location allows you to counter the ward locations to the east and west of the shown ward.

This location will allow the countering of the wards to the northeast and southwest of the shown ward of revelation.
Note that if you are attempting to counter-ward an elevated location without sight of it, you will need to use a winged courier/Tundra's Shiver for sight or a blinking hero, etc. to kill it.
You can place the ward of revelation directly on to the location of the ward of sight to avoid having to use overhead vision.
This post was edited by dude150 on Jul 17 2010 05:41pm