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_23982399_12 ( challenger VARCHAR, winner VARCHAR )

### Question ###
Who was the challenger when winner was kimio nonaga?

### Accurate SQL ###

SELECT challenger FROM table_23982399_12 WHERE winner = "Kimio Nonaga"