Pachter - Reggie told me that Wii U supports two Wii U controllers

"They were particularly unclear about whether the console would support more than one of their tablet-like controllers; Mr. Miyamoto said no, but Reggie said yes (to me in a meeting), Obviously, they intend to ship the console with only one of these controllers, so it is unlikely that anyone will develop games that require two, but they were not clear whether the capability exists." - Wedbush analyst Michael Pachter

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