You will often see references to the alleged fact that the Chinese character for ‘crisis’ is made up of the word for ‘danger’ plus the word for ‘opportunity’ (or, as here, that the Japanese character is so composed). I have no idea how this claim became so popular, but Victor H. Mair at Pinyin.info has done a thorough debunking:
The explication of the Chinese word for crisis as made up of two components signifying danger and opportunity is due partly to wishful thinking, but mainly to a fundamental misunderstanding about how terms are formed in Mandarin and other Sinitic languages… The third, and fatal, misapprehension is the author’s definition of jī as “opportunity.” While it is true that wēijī does indeed mean “crisis” and that the wēi syllable of wēijī does convey the notion of “danger,” the jī syllable of wēijī most definitely does not signify “opportunity.”… The jī of wēijī, in fact, means something like “incipient moment; crucial point (when something begins or changes).” Thus, a wēijī is indeed a genuine crisis, a dangerous moment, a time when things start to go awry. A wēijī indicates a perilous situation when one should be especially wary. It is not a juncture when one goes looking for advantages and benefits. In a crisis, one wants above all to save one’s skin and neck! Any would-be guru who advocates opportunism in the face of crisis should be run out of town on a rail, for his / her advice will only compound the danger of the crisis.
There is much more at the linked page, including some “Pertinent observations for those who are more advanced in Chinese language studies.” Many thanks to Grant Barrett for alerting me to the link; I should add that Pinyin.info has all sorts of goodies, including a list of Taipei street names in Chinese characters and Hanyu Pinyin.