Duel Disk prototype
This Duel Disk was physically different than later models. It consisted of two parts, connected by a retractable cable. One piece stored the user's Deck and was strapped to their wrist. The other part was a disk with slots for cards they put in play. Users would put the necessary cards into the slots and then throw the disk in front of them. The disk would spin and create Solid Vision projections. To change cards, the user had to pull the disk back to their hand via the cable, like using a yo-yo.
Seto Kaiba had Maximillion J. Pegasus' Mind Scan ability in mind, when developing this Duel Disk. It allowed for players to stand further apart. When using the Duel Monsters Expert Rules, it created projections of player's hands, which they could hide their faces behind. He hoped these elements would be enough to avoid having his mind read.
Kaiba brought the prototype Duel Disks with him to Duelist Kingdom, with the intention of Dueling Pegasus. When Katsuya Jonouchi challenged him to a Duel, Kaiba used it as a chance to test his Duel Disks and Dueled Jonouchi using the Duel Monsters Standard Rules. When Kaiba Dueled Dark Yugi, they used the Expert Rules.
When Kaiba insisted on using the Duel Disk prototypes for his Duel with Pegasus, Pegasus knew it was a bad idea to fight on his enemy's terms. He claimed to not be physically active enough to wield the Duel Disk and agreed to use the Duel Disk under the condition Mokuba Kaiba's soulless body hold the Duel Disk for him. Kaiba refused to fight his brother like that and agreed not to use the Duel Disks, leaving himself open to Pegasus' Mind Scan.
- Yu-Gi-Oh! Duel 101 (Duelist Duel 42): "Advance and Retreat"
- Yu-Gi-Oh! Duel 85 (Duelist Duel 26): "Duelist's Honor"
- Yu-Gi-Oh! Duel 100 (Duelist Duel 41): "Duel Disk Battle!"
- Yu-Gi-Oh! Duel 108 (Duelist Duel 49): "The First Stages of Fear!"
- "TRANSCEND GAME"
- Yu-Gi-Oh! SEVENS episode 25: "Dreams, Courage, and Friendship"