Board Thread:Episode Discussions/@comment-25319479-20170531105724/@comment-25122992-20170603214538

Dude, I think you should read the Tenseigan article more attentively. Or maybe, you're just talking not about the Tenseigan itself as a doujutsu, but about Tenseigan Chakra Mode, a chakra mode which is available through the doujutsu's power, aren't you? It surely needs hand seals to be activated, unlike the Tenseigan itself.