Since there is no concept of CAPS in Chinese, I assume you mean that Chinese and Japanese characters are more or less square-shaped (thus less "shape contrast"

Since there is no concept of CAPS in Chinese, I assume you mean that Chinese and Japanese characters are more or less square-shaped (thus less "shape contrast" from the linked article), are they harder to read? The answer is probably no for natives, but yes if you are used to latin-based languages. One thing to note though is that there are so-called half-width and full-width symbols in most Chinese fonts (I think it's the same in CJK, but not very sure). These are half-width symbols (normal symbols): 1234567890 ALL CAPS sucks There are full-width counterparts (if your system and display them): １２３４５６７８９０ ＡＬＬ ＣＡＰＳ　ｓｕｃｋｓ Half-width and full-width chars get their names due to the fact in a monospace Chinese font, two half-width chars will take the same space as one full-width char. This makes alignment easier. By now it's pretty safe to say using full-width chars is a bad idea. The readability is so low and mixed Chinese and English content is so common that people don't tolerate the ugly full-width chars any more. The norm right now seems to mix monospace Chinese glyphs (all Chinese chars have same width) with proportional latin glyphs. Unfortunately most Chinese fonts come with really ugly latin glyphs, and the remedy is to specify a latin font first (Arial and Verdana are the two most popular choices) and fallback to some Chinese font.