Lake Yamanaka (Hirano)
Classic winter sunset alignment.
No exact alignment within ±0.6° this year. Check ±1° for shoulder dates.
Diamond Fuji 2026
When the sun sits on the summit.
Diamond Fuji happens when the rising or setting sun aligns with the peak. Times below are computed from solar azimuth for each viewpoint, accurate to the day. Add 10 minutes either side of the listed time for the full optical phenomenon.
Next windows
Upcoming alignments
The next eight dates across all tracked viewpoints. Times are JST.
sunset
17:45
19 Sept 2026
Hakone Lake Ashi
Sun az 302.78° · Fuji az 302.88° · offset 0.11°
By viewpoint
Diamond Fuji per spot
Tolerance is 0.6° from the sun's center to Fuji's bearing. A wider tolerance picks up the full disc on either side of the exact alignment.
Lake Tanuki
April and August sunrise windows.
No exact alignment within ±0.6° this year. Check ±1° for shoulder dates.
Lake Kawaguchi north shore
Late October to early November sunset.
No exact alignment within ±0.6° this year. Check ±1° for shoulder dates.
Lake Sai (Saiko)
Mid November sunset.
No exact alignment within ±0.6° this year. Check ±1° for shoulder dates.
Hakone Lake Ashi
Mid January sunset, often clear.
- 19 Sept 202617:45 · sunset
Lake Shoji
Early August sunrise, Double Diamond with reflection.
- 25 Mar 202605:42 · sunrise
How it works
The maths behind the calendar
For each viewpoint we compute the compass bearing toward Mt Fuji's summit, then for every day of the year we ask SunCalc where the sun rises or sets in compass degrees. When those two angles match within 0.6°, the sun crosses the peak.
Spots west of Fuji like Lake Yamanaka see Diamond Fuji at sunset. Spots east of Fuji like Lake Tanuki see it at sunrise. We pick the right event automatically per viewpoint.
Need help getting there? See our access guides and the sunrise calendar for blue hour times.