The Why of the Weapons

[Wentos]

Leonardo trains the hardest and possesses the most self-control of the four turtles. As such, he received the katana blades, the deadliest weapon of the four. They require a firm, yet controlled hand.

Raphael is by far the most aggressive in combat. Because of this, he received the sai, a primarily defensive weapon used for blocking and parrying. To truly excel in combat requires a strong defense, as well as offense.

Donatello is the most contemplative of the four brothers. He's in his own head a little too much, and that includes during combat. As a result, he received the bo staff, the simplest and most straightforward weapon of the four.

Michelangelo is more easily-distracted than the other turtles. This is why he received the nunchaku, a weapon that requires the utmost concentration and dexterity to use effectively.

I've heard this story passed around on the internet a lot in the last few years. Does it have any basis in official TMNT canon, or is it one of those fan ideas that just gained traction and became accepted over time? Either way, I always thought it was a neat way of looking at things. I love the idea that Splinter would deliberately give the turtles weapons that suit their personalities to help them become more well-rounded fighters.

[Candy Kappa]

I don't think it went anymore beyond then: the weapons looked cool. It's the archetypical martial arts weapons. The Katana is iconic in pop-culture where even cyber punk anti heroes dual wield Katana and Vampire Hunters uses them. Elektra from Daredevil uses Sai, Nunchaku was and is highly popular because of Bruce Lee. And the staff is been in many movies and stories.

[Wentos]

Oh yeah, I totally agree that when Eastman and Laird first came up with the TMNT, there wasn't any real thought put into the weapons beyond that they looked cool.

But when new writers change and update the mythos of existing characters, they tend to put more thought into things than even the original creators did. For example, Superman's S-Shield being a Kryptonian symbol? That wasn't originally a part of Superman at all, it was originally just an S. But over time, writers came up with a new explanation for something that was originally just taken for granted.

In the same way, it's entirely possible that a writer could have come up with a new explanation for why each turtle received the weapon they did. It happens all the time when new writers want to put a new spin on things, or just want to give old ideas a fresh context.