Tackling a problem for England skipper
Hartley's latest ban came shortly before World Rugby introduced new and stiffer penalties for dangerous, head-high, tackles.
The 30-year-old accepted he would have to change his game.
"The much-documented tackle technique, I've been working very hard with England defence coach Paul Gustard] on that," he said.
"We always want to tackle low, but there are times when as a second man, low isn't an option," added the 79-times capped Hartley.
"It's about for me, my arms, bring them tighter to my body, following through with those, then the shoulder, rather than the arm,"
England head coach Eddie Jones compared World Rugby's changes to the introduction of speed cameras on roads.
"It's always been illegal to tackle the head of an opposition player, so in that sense nothing's changed," he explained.
"You put speed cameras in and what happens – hundreds of thousands of people get fined.
"A year later the fines decrease. It's the same with high tackles.
"It will be the same until people learn to 'drive safely', and safely is within the speed limit,"
Agence France-Presse
