  An isotope of the 113th element, i.e., 278[113], was produced in a nuclear
reaction with a 70Zn beam on a 209Bi target. We observed six consecutive
{\alpha}-decays following the implantation of a heavy particle in nearly the
same position in the semiconductor detector under an extremely low background
condition. The fifth and sixth decays are fully consistent with the sequential
decays of 262Db and 258Lr in both decay energies and decay times. This
indicates that the present decay chain consisted of 278[113], 274Rg (Z=111),
270Mt (Z=109), 266Bh (Z=107), 262Db (Z=105), and 258Lr (Z=103) with firm
connections. This result, together with previously reported results from 2004
and 2007, conclusively leads to the unambiguous production and identification
of the isotope 278[113] of the 113th element.
