机上

机上

"机上" means "on the desk" or "theoretical."

Here, '机上' is used literally to describe the physical location of the documents on the desk.

机上の書類は整理されている。

The documents on the desk are organized.

In this sentence, '机上' metaphorically refers to 'on the desk,' implying theoretical or conceptual planning rather than practical execution.

机上で計画を立てるのは簡単だが、実行するのは難しい。

Planning on paper is easy, but executing it is difficult.

The phrase '机上の空論' (ki-jō no kū-ron) means 'empty theories from the desk,' highlighting the impracticality of the given reasoning.

彼の理論は机上の空論だと思う。

I think his theory is impractical and not feasible.