who has won the most 5 and 6 nations
Six Nations Championship England hold the record for outright wins of the Home Nations, Five Nations and Six Nations tournaments, with 28 titles, although Wales follow closely with 26 outright wins with the addition of 12 shared victories to England's 10. Since the Six Nations era started in 2000, only Italy and Scotland have failed to win the Six Nations title, although Scotland were the last winners of the Five Nations.
Grand Slam (rugby union) In rugby union, a Grand Slam (Irish: Caithréim Mhór. Welsh: Y Gamp Lawn. French: Grand Chelem) occurs when one team in the Six Nations Championship (or its Five Nations predecessor) manages to beat all the others during one year's competition. This has been achieved 39 times in total, for the first time by Wales in 1908, and most recently by Ireland in 2018. The team to have won the most Grand Slams is England with 13.