Seals can have some pretty creative types that make them hard to read. This one is one such case. It’s hard to make out what the seal says, so my best guess is chenxi, but it could really be other things. EDIT: Someone who knows this stuff better than I do claims it’s changxi. To call this lid loose is being generous – it’s practically falling off. It comes in a nice wooden box. The words on it says “cannon spout” “white clay kyusu”. The box is from Japan but the pot I believe is a yixing. 135ml.