Sound Speed (音速 ; Onsoku) is a keyword introduced in BS51, currently exclusive to Green Spirits. It is an improved version of High Speed. The effect is worded as follows:
- Flash - Sound Speed (Either Attack Step) You can summon this card from your hand by paying the cost from either your Reserve or by paying from your Red/Green Grandwalker Nexus(es) and sending the cores to the Void.
An ability introduced together with The Grandwalker Saraswati as the key ability of her spirits. The name of the ability references both the original ability High Speed, and Saraswati's kins' feature. In the lore, Saraswati governs music, while she and her kins, the Sound Beasts, can travel swiftly at the speed of sound.
In BS52, a new variant of the ability, Absolute Sound Speed, was introduced.
Official Q&A[]
Q1: What is Sound Speed's effect?
A1: During Flash-timing, you can summon a card with Sound Speed from your hand, by paying the cost from either your Reserve or by paying from a Red/Green Grandwalker Nexus and sending the cores to the Void. The cores to be put on the summoned Spirit can be moved from your Reserve/Field.
Q2: When I'm summoning a Cost 3 Spirit through Sound Speed, can I pay the cost by moving one core from my Reserve to Trash, one core from my Red Grandwalker Nexus to the Void, and one core from my Green Grandwalker Nexus to the Void?
A2: Yes, you can pay the cost in this way.