Timing is an important aspect in Japanese calligraphy (shodo) and martial arts such as kendo. In the latter case, it is, perhaps, not surprising. In calligraphy also, I found that timing of individual brushstrokes is so important that learning the technique from the books, without a teacher, is nearly impossible.
An interesting similarity between calligraphy and kendo is that it is not the rhythm itself, but its variation that elevates the quality of technique. In kendo, varying the timing, breaking up the pattern of attacks and counter-attacks, adds the element of surprise for the opponent and makes the techniques less predictable. In calligraphy, varying the speed of the brushwork adds character to the writing, emphasizes individual characters (kanji) or certain elements of the characters and ultimately gives “interestingness” to the resulting image.