Military gorget collar patches, also known as collar tabs or shoulder boards, are insignia worn on the collars or shoulders of military uniforms to indicate a person's rank, regiment, or branch of service. They have been a prominent feature in many armed forces around the world.

Here's a brief overview of their use in various countries:

Germany (Historical): In Germany, especially during the Imperial and Nazi eras, gorget patches were worn by officers. They were usually made of metal and were worn on the collar. The design and color of these patches would signify the rank and branch of service.

Soviet Union/Russia: The Soviet Union and now Russia use shoulder boards. These are often rectangular patches worn on the shoulders. The design and color indicate the wearer's branch, rank, and sometimes specific unit.

United States: In the U.S. military, collar tabs and shoulder boards have been used historically. The Army and Air Force use a system of shoulder boards, which are usually fabric-covered with an underlying hard material. The Navy uses collar devices, which are metal or embroidered patches worn on the collar points of the uniform.

United Kingdom: In the British military, gorget patches were historically worn on the collar of the tunic. In modern times, rank insignia are usually worn on shoulder boards, and the style varies depending on the branch of service.

France: France uses a system of epaulettes (shoulder knots) as well as collar patches. The color and design denote rank and branch.

China: The Chinese military uses a system of shoulder boards and collar patches, with distinct designs for different ranks and branches of service.

Japan: In the Japanese military, collar patches and shoulder boards were used historically. They were known as "gorget patches" due to their resemblance to the historical gorget. In modern times, they have adopted a system similar to that of the U.S. with shoulder boards.

It's important to note that the specific designs, colors, and meanings behind these insignia can vary widely from country to country and have often changed over time. Different branches within a country's military (e.g., Army, Navy, Air Force) may also have their own distinct insignia.

For the most accurate and up-to-date information on military insignia, it's recommended to refer to official regulations and guides provided by each respective country's armed forces.