Mukto Chag-zam (Iron Bridge) – Drubthog Thangthong Gyalpo, popularly known as Lama Chag-zam Wangpo, was an architect, philosopher and an iron chain bridge builder.
Based on authentic references, G Tucci and R A Stein accepts 1385 as the year of birth and 1464 as year of death of Thangthong Gyalpo. According to the biographical information in the history of Bhutan, Thangthong Gyalpo was born in The Year of Wood Ox (1384) in the village of Rinchen Dingin Tibet. He started building iron suspension bridges of more than 100 metre span at the beginning of the 15th century, while in Europe, spans of more than 20 metres were regarded as significant achievement.
The 600 years old iron chain bridge, the first-of-its-kind in Mon region was constructed by Lama Chag-Zam Wangpo sometime during 1420 to 1430 over Tawang-Chu river, and named it Mukto Chag-zam (‘Chag’ means iron and ‘zam’ means bridge) in Mukto village which is situated in Tawang district of Arunachal Pradesh.
The main motivation behind this magnificent construction was his immense compassion for the people, who due to lack of bridges over various rivers in the Himalayan region, were usually compelled to cross them in small boats or other floating vessels.
During his life time, Lama Chag-zam Wangpo built over 100 iron bridges all over the Himalaya region, and Mukto Chag-zam is certainly one of them and perhaps, it is the only iron chain bridge in India built by him while such other bridges are over various rivers in the Himalaya region in Tibet, Nepal, Bhutan and other adjoining regions.
Due to the unworldly nature of its construction, the bridge needs consecration prayers to lengthen its life. The local folks even today offer prayers at the metal work site. The consecration puja for the bridge was routinely conducted by Guru Rinpoche by virtue of his association with the builder of the bridge in his previous incarnations. It is believed that the third incarnation of Guru Rinpoche was one of the three sons of Drubthog Thangthong Gyalpo. It is because of this that Guru Rinpoche conducts Rabney at regular intervals.
It is said that after the completion of the construction of a good number of Chag-zam bridges inBhutan, some iron metals and finished iron chains were found in surplus and left unused. With a view to make good use of the surplus materials for the service of mankind and animals, Thangthong Gyalpo set out for Mon region from Bhutan. He made his camp at Bherkhar, a small hamlet in Kharsanang area in Mon Tawang which is not very far from Tawang-Chu river, the construction site of Chag-zam.
As a testimony, his footprint, the skull used for performing rituals and some iron chains are still preserved in the house where Chag-Zam Wangpo stayed during the construction of the bridge.
He composed an opera called ‘Ache Lhamo’ which was performed repeatedly to collect fund and materials for construction work. The audiences, impressed with the performance of opera, donated in cash, in kind and pieces of iron for the construction. This opera is performed even today with great fanfare. Finally, he collected enough fund and iron to start the construction of the bridge.
It is believed that he extracted the service of men, gods and demons to melt and mold the construction metals, exercising his mystic and supernatural powers. The men were engaged in the day shift and the gods and demons took over at nights. The rock where the open air workshop was set up still stands there as testimony. Surprisingly, no sign of welding, which normally joins the metal to hold the bridge together, is found along the entire span of the bridge, which is strongly assumed as an indication of him being a manifestation of a heavenly being.
The villagers of Mukto, Gomkyaleng and Mirba take care for maintenance, renovation and proper protection of the bridge and even today it is regularly used by men and animals to cross Tawang-Chu.