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_23648 ( "Standard Yarn Weight System" text, "Yarn Type (US)" text, "Ply (UK, NZ, AU)" text, "m/100g" text, "Wraps Per Inch (WPI)" text )

### Question ###
Name the standard yarn weight system for 9 wpi

### Accurate SQL ###

SELECT "Standard Yarn Weight System" FROM table_23648 WHERE "Wraps Per Inch (WPI)" = '9 wpi'