OCR Model. What's "anchor-words", and how to define them?

I build a OCR Model to get the code(商品コード)] from photo. But got the warning below.

“A warning was produced while training OCR Model ‘Read Code 2’: No anchor-words were found; defaulting to using top-left corner and document size for alignment.”

My question is how to make my anchor words(I think it’s “商品コード”) to be found.

Same as me.