Translation guide
A device or system whose internal workings are hidden or not understood, but whose inputs and outputs are known. In Japanese, the English loanword ブラックボックス is common, but native expressions also exist depending on context.
Referring to a physical or abstract system where only input and output are observable, and internal mechanisms are unknown or irrelevant.
The most direct and widely understood term, used in engineering, computing, and general contexts.
This device is treated as a black box.
A descriptive phrase meaning 'a box whose contents cannot be seen'. More literal and less technical.
That system is like a black box.
Means 'something whose interior is unknown'. Used in formal or explanatory contexts.
This algorithm is treated as a black box.
Specifically the crash-survivable recording device on aircraft, often called a 'black box' despite being brightly colored.
Describing a situation where the reasoning or process is hidden, often in business, government, or algorithms.
The loanword ブラックボックス is very common and understood in technical and general contexts. It can be used as a noun or with 化する (かする) to mean 'to make into a black box'.
The system has become a black box.
Also used for flight recorders in media and general conversation, though technically the device is not black.
Analysis of the black box is underway.
The organization's operations are a black box.
The loanword is also used metaphorically for any opaque system.
AI decisions are often a black box.