It's retconning by Nintendo...as already pointed out, the Ocarina of Time Child Link has some manipulation issues with it, but the sword's been downsized to fit The Wind Waker Child Link perfectly, even one-handed.

Like the Hyrule map itself, even the Master Sword changes configuration at the game designers' whim to fit the specific needs of whatever story is being told at that moment.

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"Chuck Norris once visited Heaven. Needless to say, no one will be getting their 72 virgins."