Spoiler: showNaruto's mom has steel/metal release jutsu (that's why she used the chains to bind Kyuubi. She teaches Naruto it by combining her hairpin with his Hokage necklace, and he uses his new found Kekkei Genkai (which combines his already wind affinity with his mother's lighting affinity(she also has wind too)) to create this metal/steel release jutsu. He cuts the Kyuubi's chakra from it's will in half and masters 9 tails chakra. Those are the spoilers...
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