Doesn't sound like it's going to happen very soon, but I agree...it is a good idea to implement later on in the game. Something like this was asked for before, though it was a bit more complex, and then there was this argument that you should/shouldn't have it contribute to training for experience points. However, the key elements are relatively the same:
1. Have a room/arena where two+ players can enter and compete in a friendly fashion.
2. Have it be private/queued room into which invited/befriended players can enter.
The largest addition I can see here is that there would be the option for players to "spectate" said duels, which I guess is kind of cool, but ultimately pointless in terms of a private room. If you guys REALLY want something like that so badly, you should try asking for a Sparring Arena building--to be added in later in the game, into villages or settlements--in which players can freely come to spectate or spar. Later on--we're talking much later of course--you could use these areas for minor, non-chunin exam contests of combat skill.
Again though, this is definitely something that should/will be dealt with later on...you'd be lucky to get it in Beta. And also, if you'd have preferred to have had this answered solely by the devs/mods, let people know by saying so at the end of your post (only if you'd have preferred a single dev/mod response of course).
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