Riho Shihomi is a professional photographer who emerges as a significant mentor to Fu Sawatari. Their connection initiates when Fu sends her photographs to Riho, who replies by mailing her a train ticket without a specified destination. This ticket symbolizes Riho's philosophy that life's direction is open-ended, encouraging Fu to embrace freedom in her personal journey.

After receiving Fu's photos, Riho finds renewed inspiration, leading her to host an exhibition. She invites Fu to attend, marking their first in-person meeting. During this encounter, Riho expresses how Fu's sincere and unpolished photographic perspective reignited her own passion for the art form.

Throughout the series, Riho guides Fu, particularly on the emotional and philosophical aspects of photography. She reinforces that even technically imperfect photos hold value if they capture genuine emotion or a meaningful moment. This perspective mirrors the beliefs of Fu's late father, who cherished "tamayura" (specks of light or backscatter in photos) as representations of joy.

As Fu enters her final high school year in *Tamayura: Sotsugyō Shashin*, Riho contemplates a career shift. She plans to move to Tokyo to work at a small photography gallery, a decision she hesitates to share due to their close bond. When Fu learns of this, it prompts a heartfelt conversation where Riho reassures Fu that her growth stems from her own resilience, not solely Riho's mentorship. Riho shares her own past reliance on a mentor and eventual confidence to forge her own path, emphasizing Fu has reached a similar point of self-sufficiency.

Riho maintains connections within Takehara, notably with Tomo, the owner of a local okonomiyaki restaurant. Their frequent interactions and closeness occasionally lead to interpretations of a deeper connection. Her presence consistently serves as a catalyst for Fu's reflections on memory, legacy, and embracing an uncertain future, solidifying her role as both an inspiration and a stabilizing force in Fu's life.