Actually, these are the standard colors:
Black or Red = “hot”
White = “neutral”
Green = “ground”
The reason why “hot” can be either black or red is because the power that comes from the telephone poles into the house consists of opposite phases of 110 volts AC plus a neutral wire. So there’s 110 VAC between the black and the white wires and there’s also 110 VAC between the red and the white wires, and there’s 220 VAC between the black and the red wires. (The three wires going to the 220 VAC air conditioner outlets are black, red, and white.)
The difference between “neutral” and “ground” is that “neutral” is a wire that comes from the telephone poles (from the power company), but the “ground” wire (“earth” in British English) is supposed to be connected to a copper rod that is stuck in the ground right next to the building. (The “ground” wire does not come from the telephone poles.)
If the outlets have a “ground” wire, then the “neutral” wire and the “ground” wire are supposed to be shorted together at the fuse box. Therefore, you can use either the “neutral” (white) wire or the “ground” (green) wire to ground a computer case.
However, most buildings and houses in Taiwan don’t have a “ground” wire going to any of the outlets, and they don’t have a copper rod stuck in the ground near the building, either. But the “neutral” wire should be at the same electrical potential as “ground”.
If you can’t tell which wire is “hot” and which wire is “neutral” because of non-standard colors being used, then you can use a voltmeter, set to AC volts. When you stick one of the electrodes in one of the holes in the outlet and touch the other electrode to something concrete (like a wall for example), then if that side of the outlet is “hot”, you should see a small non-zero AC voltage. But if that side is “neutral”, then the meter should read zero volts.