The Japanese performances by the cast of tvN’s drama 100 Days of Deception have become a hot topic among Japanese viewers. To achieve natural pronunciation and intonation, the actors took lessons for months before filming, with some even staying in Japan and practicing their lines for seven hours a day.
Recently, Japanese film and drama review platforms and social media have been filled with positive comments about the cast’s Japanese-speaking abilities in 100 Days of Deception.
In particular, viewers expressed surprise at how fluently Jin Seon-kyu, who plays Sato Shinichi, spoke Japanese. Some even said his pronunciation might be the best they had heard from a Korean drama actor. Kim Yoo-jung also won over local viewers with her natural Japanese and cute way of speaking.
Since the drama is set during the Japanese colonial period and revolves around interpreting, foreign languages serve as a storytelling device that reveals each character’s personality and circumstances. The actors went beyond simply memorizing their lines, carefully distinguishing how each character had learned a language and how they used it.
According to tvN on October 28, foreign-language training began immediately after the cast was finalized. Japanese, English, and Chinese instructors provided individual lessons, while pronunciation and intonation were also checked on set. For some actors, the preparation period lasted more than a year, from the beginning of training until filming wrapped.
Jin Seon-kyu, in particular, started with no Japanese-language skills at all. He spent two months in Japan, memorizing his script for seven hours a day. He studied conversational Japanese in the mornings and practiced his lines in the afternoons. Twice a week, he also reviewed what he had learned through video calls with the Korean language coaching team.
While staying in Kyoto, he also prepared for the possibility that the local accent might influence his portrayal. The Japanese coaching team separately recruited an actor who could help him practice his lines on location. In addition to Japanese, Jin Seon-kyu learned the way Japanese people would speak Korean.
The coaching team commented, “There was so much material that we almost felt sorry for him. Even so, he managed to do it so well that all we could say was how impressive he was.”
Kim Yoo-jung, who plays Lee Ga-kyung, devoted approximately five months to learning Japanese before filming began. She took separate lessons in grammar, conversation, and script practice, attending classes twice a day. Even while traveling overseas, she made time to continue her lessons through video calls.
Her character served as the standard for her language training. For Lee Ga-kyung, Japanese and English are tools for survival, so she needed to quickly understand situations and adjust the way she spoke depending on whom she was addressing. After memorizing her lines, Kim Yoo-jung repeatedly practiced delivering them with the appropriate tone for each scene’s emotions.
Her English training also went beyond simply aiming for fluency. In keeping with the character’s background of having picked up the language by listening to others, she worked to convey the impression of someone piecing together the words she knew to communicate.
The Japanese coaching team explained that Kim Yoo-jung fully absorbed the intonation before making the language her own. As her practice progressed, she became capable of recognizing even subtle differences in intonation on her own.
Park Jin-young, who plays Kim Tae-woong, also known as elite interpreter Sato Hideo, used writing and physical movement to learn his lines. Already familiar with basic Japanese and hiragana, he memorized his dialogue by writing it out on a large sketchbook. He also practiced the movements he would make in each scene, using physical actions to help internalize his lines.
His training began in February this year and continued until filming ended. To find a speaking style suited to his character, he listened to recordings made by several people. According to the coaching team, he listened so repeatedly that the voices continued echoing in his mind even when he lay down to sleep. Reflecting on the preparation process, Park Jin-young said, “Practice was the only answer.”
A different approach was used for Lee Moo-saeng, who plays Yoo Phillip, an international journalist. His Japanese had to reflect the characteristics of a Japanese speaker whose native language is English. He had already memorized most of his Japanese lines by his first lesson and refined his delivery by studying reference videos.
Lee Moo-saeng reasoned that a journalist proficient in languages would communicate clearly and concisely. He therefore focused on delivering accurate expressions while complementing them with facial expressions and gestures. He also studied the speech patterns and body language of characters in films set in the 1930s.
According to the coaching team, the actors had mastered 12 sessions’ worth of Japanese dialogue before their first day of filming. Although their intonation was sometimes adjusted on set, they rarely encountered difficulties because they had failed to memorize their lines.
As details of the cast’s preparation emerged, the drama also continued to gain momentum in ratings and popularity. Episode 6, which aired on October 25, recorded an average rating of 9.9% and a peak of 10.7% in the Seoul metropolitan area among paid-platform viewers, according to Nielsen Korea. Both figures marked the drama’s highest ratings to date. It also ranked No. 1 among all programs airing in the same time slot across all channels, including terrestrial broadcasters.
The drama also topped Good Data Corporation’s FUNdex rankings for TV and OTT drama buzz in the fourth week of October. In the rankings for individual cast members, Kim Yoo-jung and Park Jin-young placed second and third, respectively.
Episode 7 of 100 Days of Deception will air on October 31 at 9:10 p.m. KST.
Sources: Daum