Welcome to Touhou Answers. What would you like to know?

Ran can't open or control the boundary by herself because Ran occupation is Yukari's shikigami and her ability isn't same as Yukari . Ran's abilities is black magic and shikigami ritual while Yukari's abilities is manipulation of all the boundaries.So, Yukari is the only one who are capable with boundaries but, also Maribel Hearn also can control the boundaries of the future.

I think "the" boundary was supposed to mean the Hakurei Border. It might be possible because in Silent Sinner in Blue, Ran does reach Yukari over that sea, which there are none of in Gensokyo.

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.