I'm sorry.

I'll forget it ever happened if you can at least tell me accurately what game the code was first used on and why it was added as well as by whom. Then at least I'll have felt you've learned valuable gaming history.

Gradius? Also called the Konami Code.

ok, so that's the first game and one of its common names.... but that's not good enough. I want WHY it was inserted and by WHOM.

Interesting fact, its also called the Contra Code as Contra was more popular than gradius and people mistakenly thought it started there. But it did start with Gradius and now I need the other two parts.... c'mon you're a smart kid, you can find it. Better hurry tho as Jay is trying to get you banned for it.

It is a shame you have not fought before otherwise you would know if you are a better ground or standing fighter. Since he is fat, the obvious choice is your stand up game, next comes style.

I recommend the always faithful drunken monkey style. Literally get trashed and go for his face. When his puddgy self hits you, you will feel nothing due to being a dunken monk. Practice makes perfect so get drunk every night until the match and pick fights with progressively bigger and bigger fat dudes each day. By Saturday, you will be well trained in street fighting and be ready to beat all the heavy weight out of shape fat guys of the world. Trust me I have never lost a fight!

Kazuhisa Hashimoto? He found it too difficult. 

You mentioned that you are fighting for your honor, and that this started when he called you and asshole. And you said to try and not talk you out of it... but, regardless of what insults were thrown, you shouldn't fight. You shouldn't have insulted him back, and you should have ignored his first insult. But it escalated, and got so bad to where you feel you need to fight to solve the problem.

Why not apologize first? Sure, your classmates might look down on that, but once you're done with grade school, nobody cares. It will not make you any less of a person to apologize for insulting this guy's weight. What others think of you for backing out of a fight and apologizing instead does not matter. I will say that I don't know the full situation; where you live, what it's like there, etc, but at the very least, don't put yourself into a position where you need to fight again. They are not a good solution to a problem like this.

I can't condone a fight for something like this, but if you're going to do it anyway... watch this video. It shows you how to punch without breaking your hand, and to actually do something. My masters liked to say spin + speed = power... and, that's true. This is how I learned to punch, and it works. Never leave your arm out there after you punch to give him an opportunity to grab you. Keep moving. Don't go for flashy; stick to the basics. Remember that your footwork is incredibly important. If you try to throw a punch and your feet are all over the place, it will be easy to get knocked to the ground.

Considering you are from the US, I would worry about him bringing a gun to shoot you. Especially since he is telling you to fight in 3 days, that sounds quite bizarre, and I would be suspicious - I would probably call the police since he wants to assault you somehow.