Edison format ruling
Twin Swords of Flashing Light - Tryce

Card effect (current official text)Send 1 card from your hand to the Graveyard; equip this card to a monster. It loses 500 ATK, but it can make a second attack during each Battle Phase.
Rulings
- Sending a card to the GY is a cost.
- If the first attack of a monster equipped with Twin Swords of Flashing Light - Tryce is negated by Magic Cylinder, the monster can still perform the second attack.
- If a monster that normally attacks twice like Hayabusa Knight, Gray Wing, or Tyrant Dragon is equipped with Twin Swords of Flashing Light - Tryce, it doesn't get a third attack.
- You can equip Twin Swords of Flashing Light - Tryce to Injection Fairy Lily and you can use her effect for each attack.
- If Twin Swords of Flashing Light - Tryce is equipped to a monster affected by Diffusion Wave Motion, it can only attack twice.
- If Dark Blade equipped with Kiryu is also equipped with Twin Swords of Flashing Light - Tryce, and attacks twice, and Kiryu is then detached with Combination Attack, Dark Blade can attack 1 more time (not 2 more times).
- If Airknight Parshath is equipped with Twin Swords of Flashing Light - Tryce and attacks twice, you can draw twice.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.