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