Yu-Gi-Oh! - Episode 129

Major Events

Second Duel of the "Battle City" Semi-Finals.
Yugi and Kaiba Duel in a hologram of an ancient Roman coliseum.
Continuous Spell Card "Spell Sanctuary" is in play throughout the whole duel, letting both players use face-down Spell Cards as quick play spells
When "Slifer the Sky Dragon" and "Obelisk the Tormentor" clash, the power of the Egyptian Gods is revealed: Battle City's giant TV screens explode and a vision of the past is displayed to Yugi and Seto's minds.
Spanning 6 episodes, this duel and the duel between Dartz, Yugi, and Kaiba, are the longest in the Yu-Gi-Oh! anime.

Turn 1: Yami Yugi

Turn 2: Kaiba

Draws "Obelisk the Tormentor".
Summons "X-Head Cannon" (1800 ATK / 1500 DEF) in Attack Position.
Activates Continuous Spell Card "Spell Sanctuary", allowing both players to add a Spell Card from their Deck to their hands: Yugi selects "Change of Heart"; Seto selects "Cross Sacrifice" (replace by "Soul Exchange" in the Dub). From now on as long as "Spell Sanctuary" remains in play, both players can activate any kind of Spell Card during their opponent's turn, as long as it is face down.
Sets a card.

Turn 3: Yami Yugi

Draws "Alpha the Magnet Warrior".
Yugi's hand contains "Big Shield Gardna", "Exchange", "Collected Power", "Magical Hats", "Change of Heart", and "Alpha the Magnet Warrior".
Summons "Alpha The Magnet Warrior" (1400 ATK / 1700 DEF) in Defense Position.
Sets a card.

Turn 4: Kaiba

Draws "Interdimensional Matter Transporter".
Kaiba's hand contains "Lullaby of Obedience", "Power Balance", "Obelisk the Tormentor", "Cross Sacrifice", and "Interdimensional Matter Transporter".
Activates Spell Card "Cross Sacrifice" (replace by "Soul Exchange" in the Dub), taking control of Yugi's "Queen's Knight" and "Alpha the Magnet Warrior" so he can tribute them and his own "X-Head Cannon" in order to summon "Obelisk the Tormentor" to the field.
Yugi activates Spell Card "Change of Heart", taking control of Seto's "X-Head Cannon" until the end of the turn, thwarting Seto's plans.
Seto activates his set Quick-Play Spell Card "Enemy Controller", paying 1000 Life Points (Seto: 4000 → 3000 Life Points) to take back control of "X-Head Cannon" (NOTE: "Enemy Controller" actually requires a monster Tribute to take control of an opponent's monster, not a Life Point cost)
Yugi activates Quick-Play Spell Card "Lightforce Sword", removing from play "Obelisk the Tormentor" randomly from Seto's hand for three turns. (NOTE: in the real game, "Lightforce Sword" is a Normal Trap card, not a Spell Card).
Kaiba's hand now contains "Lullaby of Obedience", "Power Balance", and "Interdimensional Matter Transporter".
It is now the End Phase, so "Alpha the Magnet Warrior" and "Queen's Knight" return back to Yugi's side of the field.

Turn 5: Yami Yugi

Draws "Life Shaver".
Yugi's hand contains "Big Shield Gardna", "Exchange", "Collected Power", "Magical Hats", and "Life Shaver".
Sets a card.

Turn 6: Kaiba

First turn that "Lightforce Sword" is keeping Seto's "Obelisk the Tormentor" removed from the game.
Draws "Y-Dragon Head" and subsequently Normal Summons it (1500 ATK / 1600 DEF) in Attack Position and activates its special effect to equip it to "X-Head Cannon", increasing the latter's ATK/DEF by 400 ("X-Head Cannon": 1800 → 2200 ATK / 1500 → 1900 DEF)
Attacks and Destroys Yugi's "Alpha The Magnet Warrior" with "X-Head Cannon".
Activates Spell Card "Lullaby of Obedience", paying 1000 LP (Seto: 3000 → 2000 Life Points) to take "Slifer the Sky Dragon" from Yugi's Deck and add it to his hand.
Yugi activates Spell Card "Exchange", allowing each player to take a card from the other's hand: Yugi selects "Slifer the Sky Dragon"; Seto selects "Life Shaver".

When Joey dreams about himself dueling, in the Japanese he says he is at 'The Domino City Tournament'.
Lightforce Sword is changed from a magic to a trap card in the English version.
Cut from the dub is a shot of Yugi looking at his face down card and wondering if that is the reason that Kaiba did not attack him.
"XY-Dragon Cannon" is shown on Kaiba's Duel Disk, in the Japanese "X-Head Cannon" is on the Duel Disk.

The following cards appeared in this episode. Cards in italics debuted here.

Yugi Muto/Yami Yugi
Monster Cards Normal Monsters Alpha The Magnet Warrior Queen's Knight Effect Monsters Big Shield Gardna^{[Notes 1]} Kuriboh^{[Notes 2]} Slifer the Sky Dragon Magic Cards Change of Heart Exchange Lightforce Sword^{[Notes 3]} Magical Hats^{[Notes 1]}^{[Notes 3]} Trap Cards Collected Power^{[Notes 1]} Life Shaver^{[Notes 1]}

Seto Kaiba
Monster Cards Normal Monsters X-Head Cannon Effect Monsters Obelisk the Tormentor Union monsters Y-Dragon Head Magic Cards Cross Sacrifice (Soul Exchange in the dubs) Enemy Controller Interdimensional Matter Transporter^{[Notes 3]}^{[Notes 4]} Lullaby of Obedience Spell Sanctuary Trap Cards Power Balance^{[Notes 4]}

Flashbacks
Monster Cards Normal Monsters Alligator's Sword Keldo^{[Notes 5]} Mudora^{[Notes 5]} Red-Eyes B. Dragon Vorse Raider Effect Monsters Big Shield Gardna Kuriboh Magic Cards Card Destruction Cestus of Dagla De-Spell Mystic Box Shrink Trap Cards Crush Card Virus Spellbinding Circle

Joey Wheeler
Monster Cards Effect Monsters Panther Warrior

↑ ^a ^b ^c ^d This card can be seen in Yugi's hand.
↑ This card can be seen when Yugi search in his Deck for "Slifer the Sky Dragon" by "Lullaby of Obedience's" effect.
↑ ^a ^b ^c This was played as a Quick-Play Spell Card. It is an Trap Card in the TCG/OCG.
↑ ^a ^b This card can be seen in Kaiba's hand.
↑ ^a ^b This was played as a Normal Monster. It is an Effect Monster in the TCG/OCG.