There is a monument to Adams at the mouth of the Okawa River, and the Anjin Festival is held in his honor every August.
The Anjin Festival has been in operation for more than 30 years. 
mnli hypothesis: The Anjin Festival has been in operation for more than 30 years.  premise: There is a monument to Adams at the mouth of the Okawa River, and the Anjin Festival is held in his honor every August.