The CBS document states that the first national flag was designed upon the request of Jigme Wangchuck and was introduced in 1949 during the signing of the Indo - Bhutan Treaty .
Jigme Wangchuck is the second Druk Gyalpo of the 20th - century Kingdom of Bhutan .
The CBS document states that the first national flag was designed upon the request of Jigme Wangchuck , the second Druk Gyalpo of the 20th - century Kingdom of Bhutan , and was introduced in 1949 during the signing of the Indo - Bhutan Treaty .