What fighting style would you choose to win in a 1-on-1, unarmed fight to the death?

No prior training, no skills, everyone starting from scratch?

Boxing.

It’s not about what’s most effective or well rounded. It’s about what will make the most difference in the shortest time.

Boxing is fundamentally simple. There aren’t so many moving parts to it. You can pick up the basic pieces to do damage relatively quickly. Sure you’ll be vulnerable to a grappler like a wrestler, judoka, or BJJ player or a multi-weapon striker/kicker like a Muay Thai fighter, but this isn’t the early UFC you’re proposing, with fighters already accomplished in their disciplines. It’s about what you can pick up in 30 days.

Krav Maga might just work, but I wouldn’t bet on it. Anything else just has too much foundational learning to do before you can start using it to any effect.

Good hands are hard to deal with. I’d start there.

Update! OP has clarified in comments that this is about adding to your current skills, not starting from scratch. In that case, I’d spend the thirty days drilling takedown defense and generally getting out of grapplers’ domain.

I’m not going to significantly improve my grappling in 30 days, so I need to do as much as I can to stay on my feet and get up if I fail at that. My Muay Thai isn’t very good, but it’s what I’ve got, so I need the space to use it.

You said I could have anyone coach me. I think Chuck Lidell would be the man when it comes to this.

Krav Maga.

This is because in a fight to death I need to fight as dirty as possible. This is what KM was developed for, an all out brawl against any person or weapon (potentially) to the death.

I’d probably ask for the current “master” of KM as he’s more likely to know more lethal and effective moves then my current teacher.

Another huge advantage of KM is the fact that it is quick to learn, this is because you can focus on what you’re naturally good at.

I would never agree to the stated rules. If I have no choice, I can’t avoid it. No way to get out of it. I would reluctantly agree assuming that disagreeing would result in death.

In that case, I would have to dedicate myself for the next 30 days to get even better with my style, so I could show up to the match with a bang!

M-4 Carbine Style, Fully Automatic with Grenade Launcher with Plenty of 60 round clips, and plenty of grenades.

H&K .45 APC Center and the special at the bottom (Perfect for the ankle)

Meet the latest style by HK, The MP7A2 Sub-machine gun. Very versatile. Can chamber different runs. There is choice here. Use same round as the M-4, or the .45. M-4 is a better choice. Who knows how many people are going to be at the match. M-4 rounds could easily penetrate several bodies.

That’s right. When I am invited to fist fight. I show up expecting a gun fight! This is the only way I would ever agree.

Burmese boxing, the native name escapes me, but it is quite simply the most brutal unarmed combat technique that has rules that exists. Every single body part is a weapon and they’re all used to incredible effect. If this were no rules, then Krav Maga. Technically it’s not completely unarmed as you should be able to use any natural weapons around to your advantage but it’s damned effective.

30 days ? That’s too short for any fancy method.

I’d say, classical boxing and or Wrestling. With sparing. Trained by an ex frontline military who had seen real action.
Any trainer you said: i’d choose Captain William E. Fairbairn.

https://en.wikipedia.org/wiki/Wi

A very big part of the training would be cardio training, Because just one fight to the death could exhaust you for days.

The advantage of this style ? Being simple but efficient.
“Put’em down them stomp them to the death. If you’re on the ground with your opponent, broke them viciously, get up and stomp them to the death”

This style is not perfect, but have been developped to train recruit in a few times, with good results. It has been battle tested. It works.

Wing Chun or Jeet Kune Do.

The trainers would be Yip Man or Bruce Lee, respectively.

The reason for this is because Wing Chun is good for defending and offense, making a good balance in a fight.

Jeet Kune Do means you have knowledge in almost all types of martial arts, and you can defend against all of them.

Defendu – Wikipedia I would mix this with old school Judo. And a healthy dose of wing chun. You need to have a good background of grappling, kicking and punching techniques that fit what you like to do. My dad trained special forces types in the 80’s to fight. He taught them elements of those styles and Filipino knife fighting. He was a very dirty fighter.

Krav Maga, nothing else can save your life, you must fight dirty to win. Either that, or “run away” fighting where you run as long as possible and only hit him when he gets tired.