Need help with Asian wood markings and date

Thank you @Couch Potato Wannabe..... I’m asking this not to doubt you but to learn.......wouldn’t the lip of the lid hold it in place?

 

not if the wood started to warp.....

 

True enough, but it can have other purposes, such as structurally supporting the shape of the wood, as komokwa mentioned, some wood can warp, or simply a design element.

Looking at how the lid was constructed, it could be made of three pieces put together to create the lid. They may not cracks, as much as joins. The strip of wood underneath could simply be to reinforce the lid and help hold the pieces together.

 

Thank you @Couch Potato Wannabe yes I would agree with 3 pieces of wood with them having such even spacing.