Speaking in an investor call following the release of Nintendo's latest financials, president Satoru Iwata admitted that Wii Music hasn't done quite as well as he'd hoped.
"I agree that Wii Music, as of now, has not achieved its true potential," he said.
His comments have come to light thanks to a new English translation of the call, to be found in its mammoth entirety here.
Iwata added that Wii and DS have both had their super-hits, but that Nintendo can't get it right every time.
"I shudder at the thought of what if Nintendo DS had not had Brain Training or Nintendogs, and if Wii had not had Wii Sports and Wii Fit," he said.
"For each of these products, we create them hoping for a winner, but it is impossible to hit a bulls eye every time."
Wii Music sales haven't exactly set the world on fire since it released last autumn.