Castle Walls

 This card has a stronger Quick-Play Spell Card counterpart, The Reliable Guardian.

---

This card is effectively the defensive counterpart to Reinforcements, and has the opposite effect of Snake Fang.

---

The first generation Spanish editions of this card had Aumenta el DEF instead of Aumenta la DEF (Increase the DEF) on the lore.

---

This castle is also shown in Royal Decree and defends against a siege in Throwstone Unit, Catapult Zone and Rock Bombardment.

---

OCG Rulings

---

If you attack an opponent's face-down monster and it is flipped face-up by battle, then you can activate cards like "Castle Walls" or "Reinforcements" before damage calculation.: Can you activate "Castle Walls" in the Damage Step to increase DEF?

Blackwing - Silverwind the Ascendant: When resolving the effect of "Blackwing - Silverwind the Ascendant", if a targeted monster has a higher DEF than the ATK of "Blackwing - Silverwind the Ascendant" - for example, if an effect like "Castle Walls" or "The Reliable Guardian" is Chained - the that targeted monster is not destroyed. If the effect of "Blackwing - Silverwind the Ascendant" targets two monsters and, at resolution, only one of the monsters has a higher DEF than the ATK of "Blackwing - Silverwind the Ascendant

Previously Official Rulings

You choose the monster to receive the DEF increase when you activate this card. This card targets.

If you activate two "Castle Walls" on the same monster, its DEF increases by 1000.