ReBirth | 8B Boulder problem at Kasagi

Japan / Kyoto / Soraku District

Highball.

Originally proposed as '4-dan or harder' (4-dan equates to 8A+/8B), this 6m-tall king line is listed as 5-dan 8B+ on Rocktopo and v13/14 in repeater's videos. Either way, likely to be one of the hardest crack boulders in the world.

Contributors
56 contributions since 31st December 2025.
TdG
37 contributions since 28th February 2026.

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Fontainebleau

8B 8B (hard) 8B/8B+ No vote
2 - 2 2

Ascents

6 successful ascents recorded.

Climber Style Ascent Date Suggested Grade
First ascent.

Proposed grade '4-dan or harder' (8A+/8B or harder).

In the midstream area of Kasagi in Kyoto, there is a big boulder with a strikingly beautiful single crack running through it. This line has been passed down for more than ten years as one of Kasagi’s big projects.

The other day, I was able to stand atop it in a style close to my ideal: a first ascent done ground up, with no spotters and only the minimum number of pads needed to cover the exposed rock. There were hardly any signs that the line had been tried before, and according to local climbers it was considered a project, so I believe this is likely the first ascent.

I named the line ‘ReBirth,’ with the hope of contributing to the development of climbing culture and offering spiritual inspiration toward creative ascents.

At the top of the rock there is an old, rusted ring bolt that was placed in the past. After climbing the line, I felt that ideally I would like to remove it, but I decided to leave it as a relic marking the history of the crag.

(Translation: ChatGPT)

References

[1] https://www.climbing-net.com/news/倉上慶大、京都・笠置ボルダーrebirth初登/

[2] https://www.instagram.com/tv/CWnvjuClijo/

Second ascent.
Third ascent.

Proposed grade V13/V14

References

[1] https://youtu.be/prsj2yDelFg