Most military maps used in Vietnam had “Grids” laid over them. LZ’s and other locations were usually given by “Grid Numbers”. The grid number location for AnKhe is BR477435. The exact location can be found using a Vietnam map that has the “BR” grid shown as an over-lay. The grid over-lay is shown with red lines on the map to the left. Remember, grid lines are NOT the usual longitude or latitude lines that normally appear on maps.
To find the exact location of An Khe using a military grid over-lay there are some basic principles. All grids use the same location method and use the South-West corner of the grid to start the location. Each square section has a value of 100 linear parts; making each side equal to the number of 1000. A half-way point on any grid side is equal to 500. There are two vertical and two horizontal red lines on the map. The yellow circled “BR” indicates the BR Grid is within the four red lines. There are also 8 other grids marked in red that surround the BR Grid. To locate An Khe, start at the lower left corner of BR Grid (located where all the grids AR, BR, AQ, & BQ meet at the large black dot at the city of Plei Kanong. Each side of a grid square contains 10 equal distances. In the example, An Khe is located at BR477435, which is actually BR 477-435. The first two letters are the grid section, the first 3 nmbers are the ( E ) East coordinates and the last 3 numbers are the ( N ) North coordinates.
Starting at the SW corner on the bottom BR Grid line (Black Dot), move along the bottom grid line to the right, (East) for a distance of .477 of the entire line, or just about half way to the far right grid line. This is the East coordinate of BR477. From that location, move up, (North) for a distance of .435 of the entire distance between the top and bottom lines. This is the North coordinate of the last three numbers of BR477-435.
Once you located the first LZ or city, it’s then easy to find the other locations by the values given within the grid. A value lower than .477 in the first three digits of the number would be farther West, a higher value than .477 would be farther East. A higher value in the last three digits of the grid coordinate would be farther North, a lower value of the last three digits farther South.