"To overcome the intelligent by folly is contrary to the natural order of things; to overcome the foolish by intelligence is in accord with the natural order. To overcome the intelligent by intelligence, however, is a matter of opportunity. There are three avenues of opportunity: events, trends, and conditions. When opportunities occur through events but you are unable to respond, you are not smart. When opportunities become active through a trend and yet you cannot make plans, you are not wise. When opportunities emerge through conditions but you cannot act on them, you are not bold. Those skilled in generalship always achieve their victories by taking advantage of opportunities."
This quote is taken from an ancient book written by my favourite strategist in Chinese history: Zhuge Liang. His genius and virtues are sounded all over the world by the historical record Records of the Three Kingdoms and the less-historical book Romance of the Three Kingdoms. But the quote above is taken from neither of those two. Instead, it occurs in Zhuge Liang's book The Way of the General.
When somebody reads what Zhuge Liang did and how well he was in the art of war, he would highly appreciate what is written above. A general must always be aware of opportunities around them, since such opportunities don't come twice. But it is very interesting to read how Zhuge Liang categorises opportunities and what is needed to deal with each of them.
Events can open opportunities – that can be clearly seen. Thus it would be very stupid not to recognise such opportunity and to respond to it. It needs deeper understanding to see opportunities hiding behind a trend, or tendency of something to happen. The insight to understand and react to what lies in the future “if something keeps happening this way”, needs wisdom, or the ability to use knowledge in action. Condition means something that has been there at the first place and makes you have advantage over your rivals. According to Zhuge Liang, it needs boldness to use this kind of opportunity.