  In the search for the exact minimum of the tachyon potential in the Witten's
cubic string field theory we try to learn as much as possible from the string
field theory in the large B-field background. We offer a simple alternative
proof of the Witten's factorization, carry out the analysis of string field
equations also for the noncommutative torus and find some novel relations to
the algebraic K-theory. We note an intriguing relation between Chern-Simons and
Chern classes of two noncommutative bundles. Finally we observe a certain
pattern which enables us to make a plausible conjecture about the exact form of
the minimum.
