I think that this yoji describes how it can feel studying Japanese sometimes. I know that when I first started, I could barely introduce myself, much less do more important things like ask where the bathroom was or pontificate on the legal status of the Ainu in late Taisho/early Showa Japan. I think the seeming impenetrability of the language, at least for English speakers, is part of what keeps otherwise capable people from its pursuit. For those people who do take the plunge, I think there's a point where you realize just how much effort goes into learning Japanese, a point where it can really feel like you're just pushing on but not necessarily making progress towards a real goal. Luckily, as I went on, I think I got a better grasp of where things were going, and my Japanese ability began to take shape. I can definitely see the same thing happening to certain other people whom, I believe, I don't need to name.
As some of you may know, a 里 (り, ri) is an old measure of distance imported from China, which the interwebs inform me is equal to roughly 4 miles. 霧, read as む(mu) here but きり (kiri) in kun-yomi, is fog. 五里霧中 is what happens when the future, represented by the 20 miles or so in front of you, is shrouded in uncertainty, represented by a dense fog.
(people studying for 1/2-kyuu, I think you're supposed to know what -ga gotoku means, right?)
1) not knowing how things are going to turn out (and being nervous about it)
2) the opposite of "shrouded in the mists of time" (ie, shrouded in the future mists rather than those of the past)
At present, the manufacturing sectors of all the developed countries are facing an uncertain future, and those regions dependent on manufacturing are the subject of particularly bleak predictions.
Often times, people will use this when trying to be encouraging. Although I feel weird saying this, especially because I've gotten so much worse at Japanese since coming back to the US, for those of you having a hard time seeing the light at the end of the Japanese-study tunnel: