Is there a difference between a non-buffered channel and a buffered channel with size 1?

Yes, there is a difference. An unbuffered channel in Go blocks the sender until the receiver reads the value, and vice versa — the receiver is blocked if the channel is empty. This ensures synchronization between goroutines.

A buffered channel with a size of 1 allows the sender to write one value into the buffer and continue working without waiting for immediate reading by the receiver. The receiver can read the value later. Thus, a buffer size of 1 adds asynchrony and reduces blocking, while maintaining the order of data transfer.

In summary: a buffer size of 1 allows the sender not to block immediately, whereas an unbuffered channel requires synchronization of sending and receiving at the moment of transfer.