明後日の方向 (あさってのほうこう, asatte no houkou) is a Japanese idiom that literally means “the direction of the day after tomorrow”. It metaphorically indicates in an ironic manner that something goes in a completely wrong and unpredictable direction. For instance, an uncoordinated person often throws a ball at 明後日の方向 (an unpredictable direction). It is also used to indicate that something/someone goes far off the point. For instance, if one says “明後日の方向に組織改革をする” meaning “reform an institution in “the direction of the day after tomorrow”, that means that the reformation is completely off the mark.
明後日の方向 consists of the two words, “明後日” and “方向” with one particle, “の” between them. The first word means “the day after tomorrow”, and the latter means “direction”.
“予想の斜め上を行く” is a synonym of 明後日の方向. Literally, it means “go up obliquely above one’s expectation”, and means that something is unexpected and off the wall. You can also use the word “想像” meaning “imagination” instead of “予想” meaning “expectation”.
Differences between 明後日の方向 and 予想の斜め上
Compared to 明後日の方向, 予想の斜め上を行く is used for something either positive or negative, and emphasises that something is unique, bizarre and/or unexpected. On the other hand, 明後日の方向 usually stresses that something is unreasonable and off the mark. Another difference is that 予想の斜め上を行く sounds more like a slang word and is mainly used on the Internet.
I kicked the ball and it flew in the irrelevant direction
The discussion is going off on a tangent.
The movie has become a big hit owing to its storyline that goes up obliquely above my expectation (i.e. unique storyline )
I sent a LINE message to my friend and got an unexpected reply
Synonyms: 予想の斜め上を行く (see above)
Synonyms in English: unreasonable, unexpected
Related words and phrases: 想像 (imagination), 予想 (expectation)