City of Twilight
Unlocking chakra is a swift action that costs 1 ki. To unlock a chakra, the player must make a level check and add their wisdom or charisma modifier (whichever is higher). The DC for this check is equal to 10 + 2x the rank of the chakra you are attempting to unlock. If you fail the level check, you still lose your swift action, but you do not spend ki.
For example, unlocking the root chakra (rank 1) is a DC 12.
You can attempt to unlock multiple chakra with the same swift action, however it makes the DC more difficult. When trying to unlock multiple chakra at the same time, the DC is equal to 10 + 2x the rank of the highest chakra you are trying to unlock, plus the sum of the ranks of each chakra inbetween.
For example, if a player is attempting to unlock the first three chakra at the same time, the DC is 16 (10 + 3×2), PLUS the ranks inbetween (1+2=3), making the total DC 19.
Maintaining open chakra is a free action that costs 1 ki. If you attempt to open a chakra and fail the level check, you do not open any additional chakra, however any open chakra remain open.