Type chart
From Pokemon World Online Wiki
All pokemon have there own types,strengths and weaknesses. When engaging in battle it is recommended to use a pokemon with an advantage over your opponent, this will result in more damage on your opponent pokemon.
There are two types of advantages: First is a single-type advantage where as a Water attack against a Ground-type Pokemon which results in double damage (2x) and the second is a double-type advantage which results in a Water attack against a Ground/Rock-type Pokemon which results in quadruple damage (4x).
