Talk:Dragon's Seal/Rulings/@comment-26021817-20150224165416/@comment-5777478-20150225021125

They are suppose to declare attack phase. Technically, a player is suppose to declare everything. Unfortunately, that makes things take way too long. Generally, when things like this occur, the attacking player just plays as if the card was played at the proper timing.

Example:  I have a monster with move on the field. The opponent attacks center without declaring attack phase. I move. The opponent just plays as if I moved b4 the attack and attacks the monster.

When the card is on the field to be viewed by anyone, its easy to continue the play. When the card comes from the hand, It tends to bring up some arguments. Cards like Sleipnir and dragobond are tougher to resolve. Though, since players are suppose to declare all their moves, the defender is in he right if the attacker fails to do so.

If you are the attacker and the opponent calls sleipnir after you attacked, I recomend asking the opponent to redo the attack for clarification. If they refuse, then the fault is with them.