Bich Dao Grotto is situated in Nga Thien Commune, Nga Son District, Thanh Hoa Province. Bich Dao Grotto is also called Tu Thuc grotto, where the scholar fell in love with the fairy. The majestic Than Dau Mountain is in Nga Thien commune, famous for the Bich Dao grotto, which is located inside.
Local legend says that this is the place where the scholar Mr. Tu Thuc met a beautiful fairy named Giang Huong. Mr. Thuc fell completely love with Miss. Huong and decided to follow her to her fairyland. He spent his most wonderful days in fairyland, but deep in the back of his mind he always missed his home village. One day he decided to go back to visit his home village, unfortunately, when he returned nobody recognized him. He didn't realize that the time on earth passed much more quickly than time in fairyland. He had been away much longer than he thought and all the people that he knew had long since died. Tu Thuc left his village and has never been seen again since.
In order to reach the grotto, you must cross a large field. When you arrive there, you will see a lot of shady trees nearby. Vines criss-cross to make natural hammocks for you to rest in before you enter the grotto, a stone path leads for some hundred meters from the foot of the mountain to the mouth of the grotto. There you will see two poems inscribed in Chinese script on the rocks outside the mouth. Le Quy Don wrote one of the poems. He was a well-known Vietnamese scholar from the 18th century. However, Le Quy Don did not inscribe the poem himself. A district chief inscribed the poem on the rock in 1905.