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Then there was Setsuna's Taijutsu. Naruto had quickly learned it was highly acrobatic. The most important feature of Setsuna's nameless style was that it relied almost entirely on her legs. Setsuna never threw a punch. She only used her arms to defend and to support her body when performing her highly flexible motions.

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Naruto ducked. Setsuna's stretched leg fell upon him. 

"Hache!"

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"Reading?"

"Negative."

By this Tiger meant they had not detected any emission of conscious or residual chakra from Setsuna. From this, they concluded the girl was neither untrained in the use of chakra nor possessing of naturally vast chakra capacity (some humans were gifted in this way, even without ninja training). There was, of course, the possibility of Setsuna just being incredibly good at concealing her chakra.

For most youkai it is extremely easy to conceal their inhuman chakra from those who are not actively looking for it.