Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_83 (type VARCHAR, course VARCHAR, date VARCHAR)

### Question ###
What type has rest day as a course and was on 21 may?

### Accurate SQL ###

SELECT type FROM table_name_83 WHERE course = "rest day" AND date = "21 may"