The Japanese clock works exactly the same as any other western clock, so the only thing that needs to be learnt is how to pronounce the words.
The reason why 4 and 9 are red is because these times have a slightly different pronunciation from what you would have expected.
The first bit is actually quite straight forward. It is a direct translation into Japanese. One has the choice to write the word in numbers with hiragana, or with kanji and hiragana. These days one can even find clocks that have the hour digits in kanji, just like the clock below. It’s a gimmick.
The second part of the clock reading skill is the minutes reading. At this stage we have only added the five-minute lots.
The only other mention would have to be that there is no word for quarter of an hour, only the word for ’15 minutes’. One could also describe the quarter of an hour time span before the whole hour as ‘so many minutes before’ the whole hour – just like in English. Don’t forget the word 前 まえ mae meaning before.
Here are all the clock times in five-minute lots:
Lami Japan 
