Every year between November to February, most of the households in Bhutan perform a compulsory annual Lochoe (annual rituals) prayer and food offering to the triple gem including local deities.
The winter phase is perfect with the harvest stored and work load at the minimum. During Lochoe, all family members assemble together and make offering with great devotion and happiness. Their neighbors and friends also join them. It is an annual merry making feast for the family that is greatly anticipated and planned with great precision.
During the ceremony, a new Lhadar/Tsendar, a white flag with three multicolored strips is hoisted on top of the house after blessing by the Lama followed by Marchang ceremony.
The main purpose of placing flag on top of the roof is to show appreciation to the local gods and seek continuous protection from them. The Tsendar is said to represent the banner of local deities.
The Lhadar/Tsendar consists of a white cloth with three colors (blue, red and yellow) strips cloths stitched on to it in horizontal stripes. The three colors represent Rigsum Goem (Chenrigzig, Jambayang and Chana Dorji). Further the flag in totality also represent Rigsum Goenpo. The Reldri represents Jampelyang (Manjushri), flag represents Chenrizig (Avalokiteshvara) and pole represents Chana Dorji (Vajrapani).
As such the flag is said to protect the house, occupants and animals from all evils.
When placing the flag the edge of the flag should face north. The edge of the Reldri is very important, it shouldn't face your house nor your neighbors' house for it brings in bad luck. You shouldn't also allow your neighbors to point their Reldri edge to your house.
In olden days, it is also said that only those house that has volume of the Domang and Gaytom Buddhist scriptures or only nobles who can sponsor a ceremonial tea offering to the monastic body were entitled to have the Reldri and Khorlo. Today, every family uses the Reldri on their flag even when they don't have Domang and Gaytom scriptures.
The new flag also convey a message that an annual ritual has been performed.