So, a rifle is a long, skinny gun that you use for shooting things far away. A Tonkinese rifle is a type of rifle that was made in a country called Vietnam a long time ago.
The Tonkinese rifle was special because it had a really long barrel (that's the skinny part at the end where the bullet comes out). This made it very accurate, which means that when you shoot it, you can hit the thing you're aiming at pretty easily.
People in Vietnam used the Tonkinese rifle to hunt for food or to protect themselves from danger. It was also used in wars that happened a long time ago in Vietnam.
Nowadays, the Tonkinese rifle isn't used as much because there are newer, better guns available. But people who like old guns and history might still use it for fun or to remember the past.
Overall, the Tonkinese rifle is just a type of gun that people used a long time ago in Vietnam. It was special because it was accurate and helped people hunt or protect themselves.