The VIETNAM WAR BLACK BOONIE HAT is part of a non-spec uniform often worn by the Junk Force Advisor squad. The Junk Force Advisors were formed in the 1960s and were a paramilitary organisation known as the ‘Black Pajama Navy’ or simply nicknamed the ‘Junkies’. The squad commonly appropriated local workwear in an effort to blend in with town folk, with the complete pajama uniform closely resembling Vietnamese farmer's clothing.

The coastal force was formed on the recommendation that the RVNN (Republic of Vietnam Police) be tasked with preventing the transportation of enemy supplies that were flowing into South Vietnam. The Coastal Force was often referred to as the “Junk Force” due to units operating on Junk boats, a sailing vessel with origins in China referred to as ‘Chu Lucs’. Using traditional vessels allowed these forces to blend in seamlessly with other coastal fishing Junks. Under the guise of local fishermen, American Advisory teams (1 Lieutenant, and 2 Chief Petty Officers) working with Vietnamese soldiers would eventually begin conducting boarding missions across rivers, seas and coasts.

There are many photographs in which American Soldiers are seen wearing the black pajamas in combination with their jungle fatigue uniforms; though some Fleet Officers disapproved of wearing any South Vietnamese Navy or paramilitary uniform, including the black pajamas. This uniform was made from a blend of cotton and linen, making it suitable for the hot climate.