Activate only while "Umi" is on the field. While "Umi" is face-up on the field, you take no Battle Damage from attacking monsters. Destroy this card when "Umi" leaves the field.
Rulings
Individual Card FAQs
"Tornado Wall" may be Set on the field if "Umi" is not on the field, but it cannot be activated. If targeted by "Bait Doll" when face-down and "Umi" is not on the field, it is destroyed.
"Tornado Wall" may be activated when "Maiden of the Aqua" or "A Legendary Ocean" is face-up on the field.
Netrep Rulings
If a player attacks “Amazoness Swords Woman” with a monster with higher ATK, the damage redirected by “Amazoness Swords Woman” will be reduced to 0 by “Tornado Wall.”
“Tornado Wall” is unaffected by “Imperial Order” negating the effect of “Umi.”
Netrep Q&As
Q: Does the errata on “Tornado Wall” mean that you are no longer protected from overflow damage from your own attacks? A: That is correct. Your Life Points would only be protected from the Life Point damage that would result from an opponent's monster that is attacking you. So if your "Gemini Elf" attacks your opponent's Defense Position "Giant Soldier of Stone," you will still lose 100 Life Points. Curtis Schultz, 01/29/2004
Trap|
Continuous