Netflix needs new subscribers. Its Korean playbook is its secret weapon.

Over the past six months, South Korea has contributed more popular Netflix programmes than any country other than the US.

It took “Squid Game” just four weeks this past fall to become the most-watched Netflix Inc. show ever released in any language. But when it comes to the streaming giant’s global ambitions, what happened afterward matters even more — viewers who devoured “Squid Game” started watching more shows in Korean.

During the week of Oct. 11, “My Name,” a drama about a woman seeking to avenge her father’s murder, jumped into the Netflix top 10 for non-English series. The following week, “The King’s Affection,” a romance set during the Joseon Dynasty, did the same. The week of Nov. 15, “Hellbound,” a