Hi all. I am a go player since 2008. I am a solid 2 kyu right now on KGS with an account with which I only play vs same rank opponents. Nevertheless, with the other account, which I use to play vs stronger opponents, I am barely 5 kyu. I often lose games at 5 stones vs 1d players, something that should not happen to 2kyus.
Is it kind of normal? Because I'm a bit frustrated...
Handicap go is something of a different animal from go on even. SOme possible sources of problems for Black:
1) Black is taking a handicap and there could be a tendency to play too cautiously, thinking he can win while suffereing small losses, or be overconfident and make a lot of unreasonable moves.
2) White is likely to make more overplays or trick plays than would happen in an even game. It could go badly for Black if White gets away with it.
I've seen it happen often that players play differently with and without a handicap. Get your lost handicap games reviewed, especially ones where you felt the rating difference should have guaranteed you a win.
It's curious, actually, infuriating that you don't mention an account for exclusively playing weaker players. I take the stance that it's a bad habit to act like learning depends chiefly or even non-negligibly on the rank of your opponent. There's uber-plenty to learn from weaker players, your peers, and afaic "beginners" in particular. But more to the point, don't look (such a high percentage of the time) to others for improvement or enjoyment, let alone looking to their rank. Your experience and development of capability to respond flexibly to a variety of situations from either color's point of view is what matters to consistent performance.
Depending on playing style it probably is. Also, I wouldn't overidentify with any rank in whatever ranking system. Regardless of certificates, the real game will always be on the board.
The secret to handicap games is to treat the stronger player as a peer. Better, for sure, you get the handicap for this very reason, but a peer nonetheless. Play solidly (not timidly) - you are ahead - and use your strength to put pressure on White as you should do with any other player. Look at professional handicap games (there are collections including 4 stone handicap games of still very young, later go heroes), take them as inspiration.
Play some games giving handicaps. If you win, find out why. If you lose, find out why. Then apply this to taking handicaps as well
I've seen it happen in my club time and time again: as the stronger player, I'd often be challenged for an even game. And during the first 50 moves or so, I invariably think "if only they would play this way in handicap".
Human psychology tends to take risk when needed and be lazy when comfortable. It's very hard actually to keep up the proper mentality under all circumstances.
On the other hand, to a player of professional strength the difference between 2k and 5k will be negligible. We tend to get very worked up about variations in the vicinity of our own rank. Would you feel a big difference in playing a 9 stone handicap against a 14 kyu or an 18 kyu? That's how much it matters in the greater scheme of things.
The difference in attitude alone may very well account for the marginal difference in level we're talking about. It could also be pure coincidence, for which the mind has provided a causal story.
I'd say you should expand your range of opponents a bit; at 2k you should be quite willing to play anyone in some range like 1d to 4k. Those might well be interesting games and would include practice on both sides of a two-stone handicap.
Also consider handing the occasional drubbing to us high single digit kyus (most of us would appreciate it) and getting one from a higher dan if possible.
My own rule is that I'll happily play anyone within six stones of my rank, either way, though I do prefer closer ranks. Plus I play the odd game against beginners to help them along.