Facing Tamsui River, Ancient Buddha Pit is located underneath Lingshan Park, with Guandu Pier, Guandu Bridge, Guanyi Mountain, and Tamsui Estuary. The pit worships Thousand- hands Avalokitesvara, Caturmaharajakayikas (Four Heavenly Kings) and 28 main deities. 28 cavities are dug out in the tunnel to worship 28 main deities. The entrance facing Tamsui River is opened with Sanchuan Door, with Mountain God of Lingshan at the altar at the left and Fude God at the altar at the right outside of the door.
Stone carvings include the stone pillars during 1736-1795mentioned above and the stone mortar placed in the middle of the passage. Some think the mortar is a relic from Pingpu Tribe; some regard it as a tool for Chinese people to grind rice; some think it is a tool for mixing the materials to fix the ship used by the fleet of Lin Da-Chun, a gentleman from Guandu, accessing to the trade in Tamsui River after it was opened.
Briefly speaking, most of stone carvings in the pit are on walls of Sanchuan Door, such as the stone lions, stone carvings of dragons and tigers, sun, moon, and qilin, etc. carved through techniques of relief and openwork carving. At both sides of Zhong Gang Door are a pair of stone elephants, large stone carvings of dragons and tigers, and stone carving of Three Kings.
The pit is opened up to the bank of Tamsui River. Main Hall of Fude God is established at the back of the pit, with the monument Record on God of Prosperity Pit, Guandu Temple. The main hall (God of Prosperity Hall) of God of Prosperity Pit worships Gods of Prosperity. The walls of the tunnel are carved with 20 exquisite reliefs; four altars worship four Gods of Prosperity: Wenbi God of Prosperity, Wuming God of Prosperity, Jilun God of Prosperity and Wanshan God of Prosperity. Heavenly Official God of Prosperity and four Gods of Prosperity mentioned are Gods of Prosperity of Five Directions. The hall at the entrance worships Fude God, Jin Bao Tong Lang next to Dragon doorway and Zhao Cai Tong Zi next to Tiger doorway.
The most unique stone carving at Sanchuan Door of God of Prosperity Pit is the gigantic stone window of dragons and tigers in openwork carving. The image of two dragons fighting for a pearl in the midst of mist and clouds is created through the techniques of freestanding, openwork carving, and hollowing out. The composition of the image is as great as a giant dragon and tiger stone carving. On the other hand, the image of two tigers wandering in the woods at the tiger side looks tranquil. Two tigers, with their forelegs straightening and hind legs bending, are about to jump up. This is a conventional style from Hui An. There are carvings of Scholarly and Military Gods of Prosperity as well as patterns of good fortunes on the walls at both sides. As classic stone lions in the south the stone lions at both sides of Zhong Gang Door look strong and powerful, showing the sophistication of being the king of beasts. The stone carvings above the gigantic stone window next to Dragon doorway are patterns of good fortunes ‘yi lu lian ke’ and ‘guang fu tian’ in 1980s. The former highlights exquisite craftsmanship whereas the latter presents sense of space through multiple layers of relief.