  We have decomposed to symmetric and asymmetric modes the mass-TKE fission
fragment distributions calculated by 4-dimensional Langevin approach and
observed how the dominant fission mode and symmetric mode change as functions
of $Z^2/\sqrt[3]{A}$ of the fissioning system in the actinides and
trans-actinide region. As a result, we found that the symmetric mode makes a
sudden transition from super-long to super short fission mode around
$^{254}$Es. The dominant fission modes on the other hand, are persistently
asymmetric except for $^{258}$Fm, $^{259}$Fm and $^{260}$Md when the dominant
fission mode suddenly becomes symmetric although it returns to the asymmetric
mode around $^{256}$No. These correlated "twin transitions" have been known
empirically by Darleane Hoffman and her group back in 1989, but for the first
time we have given a clear explanation in terms of a dynamical model of nuclear
fission. More specifically, since we kept the shape model parameters unchanged
over the entire mass region, we conclude that the correlated twin transition
emerge naturally from the dynamics in 4-D potential energy surface.
