How do I bet on the yen vs. USD?

[MrMore]

Obviously I have no background in this. Nonetheless, in the same way that I bet sports futures sometimes, I'd like to bet that the yen appreciates against the dollar over the next few years. And yes, I'd like a long timeframe like that, so as not to get punished by noise. I'd like to bet about 10k, and don't mind the risk. Let's say I'd like to structure the bet so as to make at least 10x return if I'm right, that the yen rises by at least 10%.

Because I can't walk into a casino and make this bet, can someone explain the mechanics of making such a wager with, I presume, a broker of some sort?

Thanks.