The code’s effectiveness was not absolute — it was contextual, specific to the circumstances of the Pacific war.

This contextual nature of the code’s security is one of the things that the simplified version of the story tends to obscure.

“The code Japan could never break” is true and accurate as a historical statement.

It should not be read as a claim that no enemy could ever have broken it, or that the code would have been equally secure in any other context.

The security was real.

It was also historically specific.