a measuring box
changed my mind
masu kote | funbetsu kawaru | tsukimi kana
[Entrance to the Sumiyoshi Shrine, Osaka]
A masu is a square wooden measuring box for rice that can be of various sizes (the smaller ones are sometimes also used for drinking sake). The Sumiyoshi Fair (held at the Sumiyoshi Shrine in southern Osaka) was famous for selling such boxes and other household utensils.
Masu were used both in the home and by merchants. So the haiku could mean that Basho says jokingly he will stop being a haiku master and instead become a merchant now that he has bought a measuring box.
Another interpretation (that I favor) is that Basho means he is enjoying the lively Sumiyoshi market so much, buying a measuring box (and looking for other things as well) that he has lost interest in moonviewing - he prefers to stay among the boisterous crowds instead of silently and lonely gazing at the moon. In reality, of course, Basho felt ill after visiting the market and therefore used this haiku as an elegant excuse for not attending.
The haiku stone stands in Sumiyoshi Park, to the south of the Sumiyoshi Shrine.
Access: A few minutes walk from Sumiyoshi Taisha Station on the Nankai Main Line, or from Sumiyoshi Torii-mae Station on the Hankai Line.