Koichi Hirose (Echoes) (広瀬康一(エコーズ) Hirose Kōichi (Ekōzu)) is the fourth story arc in Diamond is Unbreakable.
Koichi and Okuyasu are extorted by Tamami Kobayashi whom wields the Stand The Lock. However, when Josuke exposes his scam, Tamami flees. Tamami then draws in Koichi's mother and sister, and provokes the hatching of Koichi's Stand into Echoes which can implant sounds into objects and people. When Koichi manages to lift his mother's guilt, Tamami surrenders to Koichi.
|Jotaro Kujo||Akira Otoishi||Koichi Hirose||Tamami Kobayashi||Okuyasu Nijimura|
|Josuke Higashikata||Police||Koichi Hirose's Mother||Ayana Hirose||Mr. Hirose|
|The Lock||Echoes|| Echoes
- 019 (284). Koichi Hirose (Echoes), Part 1
- 020 (285). Koichi Hirose (Echoes), Part 2
- 021 (286). Koichi Hirose (Echoes), Part 3
- 022 (287). Koichi Hirose (Echoes), Part 4
- 023 (288). Koichi Hirose (Echoes), Part 5
- 03 (31). Koichi Hirose (Echoes)