Yama no Susume: Kabette Kowakunai no?

Synopsis (en anglais)

Aoi Yukimura and her friends decide to take on a new challenge: indoor rock climbing! However, the sight of the wall flusters Aoi, who frets over its height and complexity. Fortunately, Kaede Saitou is there to explain the rules of indoor climbing, inspiring the girls to give it a try themselves. Though the wall may seem intimidating and insurmountable, Aoi finds that with a little help from her friends, she may be able to overcome this challenge. (Source: MAL Rewrite)