How often do you attack the Aleutians?

I like to do it. Always with two Inf though. Is silly to use just the one. I think the U.S. has to react within two turns.

Only when the circumstances are favorable to such a move, which in my opinion, is not often the case. I’d never do it if the US could sink my transport. And otherwise, I’d consider the opportunities I might miss elsewhere. It’s often an antipositional move: the transport and the troops it carries move away from where most of the fighting typically happens.
So I’d do it when (a) for some reason, the US is having a hard time recapturing the Aleuteans, and/or (b) as a part of a broader attack that could also be aimed at, say, Alaska. My guess is that both typically occur when Japan is doing rather well anyway.

We play differently Herr KaLeun. I do it to disrupt and annoy the American player. I expect to lose the TT, but in turn to sink his relief force. Then he has ground units somewhere useless!

If the US will send a relief force and you can safely sink it, that’s wonderful. But maybe, the US can prepare to sink the sinkers of the relief force. Or maybe, the US can just start to threaten to recapture the Aleutians from SF. If there is such a threat, are you going to keep an even larger Japanese force in SZ6 to counter that? That could lead to an arms race under circumstances that favor the Americans.
Or maybe, the US can just send a plane after the transport and ignore the Aleutians for a few turns. Transport down plus 2 marooned Japanese inf = 13 IPC out of the units that are already on the board, versus -5 a round of future income for the US. I’d say that losing the Aleutians for 3-4 turns as the US is not a bad trade under those circumstances.
But admittedly, it depends. It’s hard to say in general terms.

It is simply annoying as wittmann said.
It is a thorn in an US players eye. Of course is it a waste of 13 Ipc but worth the effect it does.

I like to have at least the threat of it in place. If I can.

If the USA ignores it (going ‘all in’ south) I take it, if they position so that they can recapture immediately, I don’t ;-).

Do any of you guys move the 2 infantry there, then send the empty transport back to SZ 6, saving the transport but stranding those 2 guys? This is on the occasional chance that the US has nothing in range to kill the transport so you have time to run it back to safety. Like if the US is “going all south” like Leclerc mentioned.

HI knp. I would pull the TT back, unless the US did not have a Mech in the West ir a second TT. In which case, I would drop one of my adventuring Inf units in Alaska.