This connector is the standard for many pre-DOS/V (IBM compatible) computers in Japan. The PC-9801, X68000 and FM Towns all used this pinout, or similar variants of it. Pay attention to the differences, they are important!

NOTE the numbers are usually visible on the connector itself. If you're looking at the business end of the female connector, pin 1 is on the right. On a male connector it's on the left.

• Ys = computer data present. Usually +5V

The PC-9801 connector is nearly the same as the X68000. The differences are very minor: pins 9 and 13 are used for the 9801, but are not connected on the X68000.

• Ys = computer data present. Usually +5V

• Note that some FMTowns systems used a VGA connector.
• Ys = computer data present. Usually +5V

• Not all systems put out power on pin 7. Normally +5v, some devices (like the X-RGB2) leave this pin disconnected. You can add power to your cables, for monitors that require it, following these directions.
• Remember that the pin numbers are almost always found on the connector itself.

Credit:

• Some of this info came from this Japanese page.