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.
この装置はブラックボックス化されている。
This device is treated as a black box.
A descriptive phrase meaning 'a box whose contents cannot be seen'. More literal and less technical.
そのシステムは中身が見えない箱のようなものだ。
That system is like a black box.
Means 'something whose interior is unknown'. Used in formal or explanatory contexts.
このアルゴリズムは内部が不明なものとして扱われる。
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.
The standard term for flight recorder. Often used alongside ボイスレコーダー (voice recorder).
事故調査のためにフライトレコーダーが回収された。
The flight recorder was recovered for the accident investigation.
Describing a situation where the reasoning or process is hidden, often in business, government, or algorithms.
Means 'opaque process'. Commonly used to criticize lack of transparency.
その決定は不透明なプロセスで行われた。
The decision was made through a black box process.
Literally 'can't see the contents'. Used metaphorically for systems or organizations.
その組織の運営は中身が見えない。
The organization's operations are a black box.
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'.
システムがブラックボックス化している。
The system has become a black box.
Also used for flight recorders in media and general conversation, though technically the device is not black.
ブラックボックスの解析が進められている。
Analysis of the black box is underway.
The loanword is also used metaphorically for any opaque system.
AIの判断はしばしばブラックボックスだ。
AI decisions are often a black box.