open the kimono
v. To open a company's accounting books for inspection; to expose something previously hidden.
Other Forms
Most of the alliances, says Paolini, are legally formalized because of the need for both parties to "open the kimono" and discuss sales figures, proprietary research and financial figures.
—Laura Fowlie, “Strategic alliances wave of the future,” The Financial Post (Toronto, Canada), October 22, 1990
There's a certain paradox here. When both partners are equally intent on internalizing the other's skills, distrust and conflict may spoil the alliance and threaten its very survival. That's one reason joint ventures between Korean and Japanese companies have been few and tempestuous. Neither side wants to "open the kimono."
—Gary Hameletet, et al., “Collaborate with Your Competitors — and Win,” Harvard Business Review, January 01, 1989
1984 (earliest)
I think users have benefited in the sense that they will see new ideas and new levels of capability being brought in that they would probably never have seen. The breakup is forcing AT&T not only to get competitive, but to be willing to open its kimono and talk more thoroughly about its plans.
—“Puitting the Pieces Together,” Computerworld, July 04, 1984