According to
Douglas Hofstader's book,
Gödel, Escher, Bach: An Eternal Golden Braid, u-mode is
one of the three modes of human action ( the other two being
i-mode and
m-mode ).
u-mode stands for Un-mode which is the Zen-like mode of operation.
"One day Unmon said to his disciples, "This staff of mine has transformed itself into a dragon and has swallowed up the universe! Oh, where are the rivers and mountains and great earth?"
-- Gymon M. Kubose, Zen Koans, p 35.
see also: i-mode, m-mode