The numeric keypad is found on the right-hand side of many computer keyboards. Because the numbers 1–9 on this keypad form a 3×3 square, it is possible to think of the ‘5’ in the center as ‘neutral’ and the other numbers as directions relative to it. In fact, it is possible in some instances to use these keys as arrow keys.
The origin of using numbers to represent directions lies in the fact that back in the day, arrows were not usually found in character sets, and even if they were, they could be difficult to type and/or view, and they were generally ugly and hard-to-understand, especially in fighting games (still are: cf. ↓↘→ and ; even fancy ASCII art doesn’t tend to look as good as the inline images that can be used on the Web, etc. and to this day, text-only guides generally resort to word- and letter-based representations for directions to avoid confusion, if not numpad notation).
Before the World Wide Web made willy-nilly images acceptable, (usually text-only) Internet communications tended to make any form of arrows rather unwieldy for these reasons. And fighting game command lists were no exceptions.
The directions are as follows:
The ‘N’ in the middle of the diagram stands for ‘neutral’, though this is not universal and you will sometimes see it as 5.
This notation is used in many text-heavy media such as Japanese-style BBS’s and forums (where posting the images may be forbidden or just plain inconvenient). Some strategy sites (particularly in Japanese) make extensive use of it as well. In this notation, you will see listed as ‘236’.
This number layout is also found on most calculators, but it is different from what you find on phones and such (which have the numbers flipped from a numeric pad up and down). If you need to refer to a keypad to memorize this notation, you should keep that in mind....