[ryuurui]

Katakana and numbers (unless written in kanji) should not be used in 書道, as it is considered vulgar. That also goes to simplified kanji.

Kana is very beautiful, although it is a very demanding art. It requires mastery of 草書 (cursive style) especially that Japanese kana (and there are many more variations of it than just hiragana, such as hentaigana, to give one example) is based on it.

There is not enough time in one's life to embrace the vastness of the calligraphy world, even if you would have devoted yourself to it completely. Indeed, studying it is time consuming, but also very rewarding at the same time.

See, many people study calligraphy with an aim, such as reaching level of 師範 (instructor), where in fact sho ought to be aimless and selfless way of life. Ironically, 師範 level is a starting point of studies, and not its end. This shows how many people actually either misunderstands the whole philosophy if sho or simply they are not ready mentally to understand it.