Tanabata Yukata Festival

The Tanabata Yukata Festival is a July observance that the detectives consider while investigating possible reasons Mutsuo Koshikawa might have visited Nihonbashi Bridge. Its relevance proves circumstantial rather than evidentiary: the festival covers a wide area and has no direct connection to the bridge, leaving the proposed link unresolved.

Timing and Customs

While traveling past Nihonbashi Bridge, Shuhei Matsumiya asks whether a special event is held there for the Tanabata Star Festival. Kyoichiro Kaga identifies the Tanabata Yukata Festival and explains that July 7 has been officially designated yukata day. Customer-facing staff at local travel agencies and banks wear light summer yukata to work on that date.

Investigative Relevance

The custom prompts Matsumiya to wonder whether Mutsuo Koshikawa might have come to Nihonbashi Bridge that day. Kaga distinguishes the festival from the bridge, however: it takes place across a comparatively broad area and has no direct connection to Nihonbashi Bridge. The possibility therefore does not establish that Koshikawa visited the bridge for the festival.

Role in the Investigation

The exchange shows the detectives testing an ordinary public event as a possible explanation for a person’s movements, then narrowing the theory when the geography does not support it. Matsumiya is both impressed by how much research Kaga has done and disappointed that this lead does not yield a bridge-specific link. The festival remains contextual detail, not a solution to the investigation.