How long would it take Goku to master a new martial art?

[Zephyr]

About one time-skip.

[Kendamu]

Son Goku learned the Kamehameha pretty much instantly, but it took him awhile to get it looking like Muten Roshi's. Then, he starting doing his own thing with it. That took many years, but we'll skip ahead to when he's an adult.

His learning something like the Kaio Ken and Spirit Bomb is basically the equivalent of learning a new martial art in the world of Dragon Ball. That took him about a year as an adult. I'm taking this in the sense of how learning martial arts works in old Kung Fu movies (which has a ton of parallels to Dragon Ball). He went from not being able to handle the gravity to mastering the fighting techniques of someone higher than God in eleven months. Then, he went onto making Kaio Ken work with multitudes of effectiveness unheard of by even the technique's creator (who didn't even master the original version) in a little under a week.

This is mostly because he had senzu and didn't need recovery time to take advantage of a Zenkai so it would naturally take much longer if he had to train like a normal person. Taking all that into account, though, Son Goku would likely be able to learn the basic fundamentals of techniques almost instantly. It would just take a year or three for him to actually master the technique. Then, maybe another year or three of non-Zenaki-abuse training for him to take what he learned and expand on it to the degree that only a combat genius could.

I say a year or three because it depends on how many techniques are being mastered and what kind of techniques they are. If it's something brand new like Instantaneous Movement, then it's gonna take a little longer than it will for him to do something like take the Super Saiyan transformation, which he's used to doing, and going beyond its intended use into new territory.

The same could be said for a lot of really dedicated martial artists in real life. A guy who is learning an armbar for the first time might take a long time getting all the nuances down even if he can mimic the main ideas of an armbar just after one class. It might take him awhile to use it successfully against a resisting opponent, too. However, once it becomes something he can do without issue, he might start getting creative and using the setup as a ruse for a Snake in the Grass choke, which may not take him nearly as long as it did to learn the original armbar in the first place.

[dbgtFO]

His learning something like the Kaio Ken and Spirit Bomb is basically the equivalent of learning a new martial art in the world of Dragon Ball. That took him about a year as an adult.

It actually took him less than ½ a year, as he first had to traverse Snake Way and then catch Bubbles, which left him with 118 days to master the Kaio-ken and Genkidama.

[Kendamu]

His learning something like the Kaio Ken and Spirit Bomb is basically the equivalent of learning a new martial art in the world of Dragon Ball. That took him about a year as an adult.

It actually took him less than ½ a year, as he first had to traverse Snake Way and then catch Bubbles, which left him with 118 days to master the Kaio-ken and Genkidama.

Just like Kaio himself, I forgot to factor in travel time.

In that case, you can shorten my "year or three" to "half a year to about two years."