and the worst policy of all is to besiege walled cities 4 The rule is not to besiege walled citi

“and the worst policy of all is to besiege walled cities. 4. The rule is, not to besiege walled cities if it can possibly be avoided.”

“The Art of War by Active 6th Century B.C. Sunzi.” Gutenberg.Org, https://www.gutenberg.org/ebooks/132. Accessed 16 July 2021, loc. 57.

As already stated elsewhere, if in a self-defense situation, your enemy cloisters, maximize your distance until you are out of combat range.