A First Turn Kill is similar to a One Turn Kill, but this is pulled off in a player's first turn, even the first turn of the Duel. "Chaos Emperor Dragon - Envoy of the End" was capable of this when it was legal if you had the right cards to go with it such as "Graceful Charity" and "Card Destruction". It is also possible to win on your first turn by obtaining all five "Forbidden One" pieces during your first draw phase, but this is unlikely to happen.
Other "First Turn Kill" decks are the "Magical Scientist First Turn Kill" and the "Dark Magician of Chaos First Turn Kill". The "Magical Scientist First Turn Kill" deck consists of mainly Spell Cards that utilize the summoning of Catapult Turtle and Magical Scientist. "Dark Magician of Chaos First Turn Kill" abuses "Dimension Fusion", "Spell Economics" and possibly "Toon Cannon Soldier", "Cannon Soldier", "Catapult Turtle" or "Mass Driver". The "Magical Scientist First Turn Kill" no longer exists in the Advanced Format as "Magical Scientist" is Forbidden, and the same goes for "Dark Magician of Chaos".
New "First Turn Kill" and "One Turn Kill" decks are available after the release of "Cyber Valley" in the booster Phantom Darkness. New tactics like Rescue Cat Burn and Banisher Mill innovate in the field of FTKs with complex new strategies
These kind of decks are considered "broken" and frowned upon by many duelists because of the absence of skill involved with the duels themselves, especially at a high rate of success. First, FTK users either have to hope they go first and kill their opponent that first turn or they hope they survive and try again. This relies a lot on luck rather than skill on the FTK user. Second, it completely ignores both the opponent's deck and the Side Deck. They can have the best deck in the metagame or all the tech cards to counter the FTK, but the chances of success for the opponent is still slim.
Here are some First Turn Kills:
Types of Monster Cards
Types of Spell Cards
Types of Trap Cards
Other Types of Card
ATK - DEF - Level - Attribute - Type
Playing Field Zones
Types of Summon
Types of Monster Effects
Types of Effect Monsters
Types of Spell Speed
Aqua - Beast - Beast-Warrior - Dinosaur