Scouts/Cavalry Defence

Contrary to above post some research has shown an exception to the scout weakness rule.
A Scout and Cavavlry defence is tne most effective against archery attacks of the kind being sent by some enemies. Its effective against most kinds of mass archery attacks including rainbow.

You need lvl10 horseriding and compass.

You need 100K scouts and 50k cav. This can take out up to 100k archers with few or no losses of cav.
Level of hero and some other techs do make a difference to out come so do read forum for further guidelines.