Forum:Effects?

ok, buddy and i got confused on this, on effect monsters, if the effect does not state a time to use, can it be used at anytime? ie: vw - tiger catapult states "By discarding 1 card from your hand, change the battle position of 1 monster on your opponents side of the field." does this mean i can only use it on my main phase or can i use it at anytime i want, like when my opponent goes to his battle phase?Angeldyos (talk • contribs) 15:04, December 19, 2010 (UTC)