This is interesting. An old passwords file was found in a BSD 3 source tree, and some modern folks proceeded to crack the password hashes inside the file. They were able to crack many of them, but Ken Thompson’s password remained elusive. A few years later, armed with more powerful computers, Ken Thompson’s password was finally cracked. It turned out to be a coded form of a common opening move in Chess. Ah, Ken Thompson, you thought you’ve picked among the most secure and uncrackable passwords, but now it was finally cracked.
Of course, chances are that Ken Thompson would have changed his Unix password many times since then, so no need for security worries.
20191018/https://www.theregister.co.uk/2019/10/09/ken_thompsons_old_unix_password_cracked/