Across the country, the accident has already caused much soul-searching over Japan's attention - some would say obsession - with punctuality and efficiency.
Were this a real-life drama, it would no doubt have caused great controversy and soul-searching for the officers.
The episode caused painful soul-searching among foundation workers committed to environmental causes, but they say it has been put behind them.
The case has caused alarm and soul-searching in a nation that, while generally safe, has witnessed some spectacular killings in the last few years.
It caused anguished soul-searching in the United States.
An illegal immigrant has caused soul-searching in liberal Sweden by winning around £100,000 in a televised national lottery contest.
It is in this context that Mr. Merz's comment has caused such soul-searching.
Such droughts against the also-rans of the National League will surely cause much soul-searching.
But this wealth has caused soul-searching about the group's core purpose.
"That has caused serious soul-searching by the community."