Tanabata Star Festival

The Tanabata Star Festival enters the investigation as a possible explanation for why Mutsuo Koshikawa might have visited Nihonbashi Bridge in July. It offers a calendar-based lead, but the detectives distinguish the festival’s surrounding activity from any event specifically tied to the bridge, leaving the proposed connection unconfirmed.

Festival and Setting

At Nihonbashi Bridge, Shuhei Matsumiya considers whether July’s Tanabata Star Festival might account for a visit by Mutsuo Koshikawa. Kyoichiro Kaga identifies a related observance, the Tanabata Yukata Festival, and explains that July 7 is designated Yukata Day. On that date, customer-facing employees at local travel agencies and banks wear light summer yukata to work.

Investigative Lead and Limits

The custom makes it plausible that Mutsuo Koshikawa could have been in Nihonbashi on July 7. Yet Kyoichiro Kaga emphasizes that the yukata festival covers a wide area and has no direct connection to the bridge itself. The possibility therefore remains a hypothesis based on timing, not a confirmed explanation of his movements.

Narrative Significance

The exchange shows the investigation testing a mundane, date-specific possibility against the geography of the case. A festival can suggest a reason for someone to be in the district without establishing why they came to the bridge. In this instance, the lead narrows rather than resolves the question: the July observance offers context, but no evidentiary link to Mutsuo Koshikawa’s presence at Nihonbashi Bridge.