Here is the full list of all 20 Legendary Mahjong achievements.
Get the highest rank.
Restore the Temple of Water.
Restore all the temples.
Unlock the Celestial Gate.
Restore the Temple of Time.
Restore the Temple of Wisdom.
Undo 100 moves.
Restore the Temple of Air.
Match 10000 tiles.
Restart 5 times.
Match 10 Ice Tiles.
Restore the Temple of Earth.
Open 10 Box Tiles.
Restore the Temple of Fire.
Use 10 Magnet Tiles.
Match 10 Lock Tiles.
Get a new rank.
Match the first 2 tiles.
Complete all levels in all the temples.
Use 10 Whirlwind Tiles.