Many Westerners seem a bit lost when it comes to making the distinction between Chinese, Japanese and Korean characters, even though it is very simple! Without going into technical considerations, here are a few « tricks ».
First, it is a matter of writing direction.
Although, Korean, Chinese and Japanese used to read from right to left and from top to bottom (see Figure 1), it is no longer the case nowadays. Modern Korean and Chinese have adopted the reading direction of most Western media, i.e. from left to right and from top to bottom (see Figure 2). As for modern Japanese, it now reads from right to left and from top to bottom (see Figure 3).
So all you need is to identify punctuation and then deduce how you’re supposed to read it.
Second is the way the characters look.
Take a basic sentence: « I like vanilla. »
In Korean, it translates into « 난 바닐라 좋아 ». The characters have relatively few strokes, and consist mostly of squares, dots, L-shapes and lines that overlap in various ways, making it look very « round ». But there is an exception here: the fifth character, which looks more complex. The reason why is that much of the vocabulary outside of everyday language comes from Chinese.
In Japanese, it translates into « 私 は バニラ の よう ». Here the characters are mainly composed of one to two strokes and look very fluid. Again, there is an exception: the first character. Why? As in the previous example, many words originally came from Chinese. These characters are called kanji, as opposed to the other characters that are called kanas.
In Chinese finally, this phrase translates into « 我喜欢草莓 ». Sinograms are obviously more complex and have a very square shape. They also represent ideas (which is why they are called ideograms), unlike Japanese and Korean characters which mainly transcribe sounds (called phonograms) (excluding those words borrowed from the Chinese language, obviously).
Et voila! Without speaking a single word of these three languages, you now have all the keys to distinguish written Korean, Japanese and Chinese!