4. The proper season is when the weather is very dry; the special days are those when the moon is in the constellations of the Sieve, the Wall, the Wing or the Cross-bar; for these four are all days of rising wind.

時者天之燥也日者宿在箕壁翼軫也凡此四宿者風起之日也

Sun Tzu

Sun Tzu suggests that the “proper season” for military action is during dry weather, as wet conditions can hinder movement and make it difficult to carry out operations.

Sun Tzu also mentions four specific “special days” that are favorable for military action: those when the moon is in the constellations of the Sieve, the Wall, the Wing, or the Cross-bar. These constellations are associated with rising wind, which Sun Tzu suggests can be advantageous for military operations.

Act when the market is favorable and seize upon special opportunities with strong consumer demand, favorable conditions, or a unique advantage.

The proper time to take action is when the market is favorable; the special opportunities are those when there is strong consumer demand, favorable market conditions, or a unique advantage that can be leveraged. These are all times when it is possible to make significant progress and achieve success.

In order to be successful in business, it is important to choose the right time to act and to identify and seize upon special opportunities as they arise. This might involve considering various factors such as consumer demand, market conditions, and any unique advantages that a company has in order to determine the best course of action.