Highlight: Most of the temples at Mỹ Sơn were made of red brick, and only one (the temple labelled “B1″) was made of

stone. Even the decorative carvings on the Cham temples were cut directly onto the bricks themselves, rather than onto sandstone slabs inserted into brick walls as is observable for example in the 9th century Cambodian temple of Bakong.

To this day, the construction techniques used by the Cham builders are not completely understood. Issues that have not been completely resolved include issues about the firing of the bricks, the mortar between the bricks, and decorative carvings found on the bricks.

The temples at My Son are made of a reddish brick. Decorative carvings have been cut directly into the bricks.

At what point in the building process were the bricks hardened by fire? Were the bricks hardened first, and then arranged in order to build the structures, or were the structures built out of partially hardened bricks, after which the entire structures were heated by fire to finish the hardening of the bricks?

The hypothesis that the entire structures were reheated following assembly is supported by evidence that the mortar between the bricks was at some point subjected to high temperatures. The contrary hypothesis is supported by the observation that the structures bear no signs of scarring from large intense fires such as would be needed in order to reheat them as whole.

How were the bricks stuck together? One hypothesis is that the builders at Mỹ Sơn developed a way to glue bricks together using tree resin native to central Vietnam. Another hypothesis is that the builders used a sticky mortar made from the same clay as the bricks themselves. www.vietnambiketours.asia, The latter hypothesis is supported by chemical tests that have found no trace of any organic substance between the bricks, but instead have found mineral substances similar to those present in the core of the bricks. Today the mortar that once held the bricks together has largely decayed, and even a strong wind can knock loose bricks from the structures.

At what point in the process were the decorative carvings made? Were the walls constructed and then carved, or were the bricks carved first and then assembled so as to create the walls? An examination of the carvings reveals no broken lines as would be expected if the bricks were carved first and then assembled; and as a result scholars have concluded that the Cham craftsmen made their carvings directly onto finished brick walls