This is the 5615th most frequent Japanese word.
さかのぼり
"さかのぼり" means "going upstream" or "tracing back."
In this sentence, 'さかのぼり' (retroactively, tracing back) is used in the context of investigation, meaning going back to past events or data to gather information.
そのケースについてさかのぼり調査をしました。
We conducted a retroactive investigation about that case.
Here, 'さかのぼり' is used metaphorically to describe physically going upstream, tracing the river backwards from its flow.
川をさかのぼっていくと古い橋があります。
If you go upstream along the river, there is an old bridge.
The word 'さかのぼり' is used in the context of time, indicating going back in the timeline to review or analyze past occurrences.