ELI5: Explain Like I'm 5

Japanese army and diplomatic codes

Okay kiddo, so you know how when you want to talk to your friends and you don't want anyone else to understand, you might use secret codes or a secret language that only your friends know, right? Well, adults do the same thing sometimes, especially in important jobs like the military or in politics.

During World War II, Japan had their own secret codes that they used to send messages between their army and diplomats, who are the people who handle relationships with other countries. These codes were really complicated and hard to understand, kind of like a puzzle with lots of different pieces that need to fit together just right.

By using these codes, the Japanese army and diplomats were able to share information with each other without worrying about the enemy intercepting the message and understanding what they were saying. This was really important because during a war, knowing what your enemy is planning can give you a big advantage.

However, the United States was able to crack the Japanese codes, which means they were able to figure out what the messages were saying. This was a really big deal because it gave the U.S. valuable information about what the Japanese were planning to do during the war.

In fact, it was the cracking of one of the Japanese codes, called the Purple code, that helped the U.S. learn about the planning of the attack on Pearl Harbor, which is what really got the U.S. involved in the war. So, by cracking these codes, the U.S. was able to learn important information that helped them win the war.