  Generalizing both Dirac's condition and Ore's condition for Hamilton cycles,
Chvatal in 1972 established a degree sequence condition for the existence of a
Hamilton cycle in a graph. Hoang in 1995 generalized Chvatal's degree sequence
condition for 1-tough graphs and conjectured a t-tough analogue for any
positive integer t at least 1. Hoang in the same paper verified his conjecture
for t at most 3 and recently Hoang and Robin arXiv:2303.03479v2 verified the
conjecture for t = 4. In this paper, we confirm the conjecture for all t at
least 4.
