Last week, J-pop singer-songwriter and music producer Kenshi Yonezu made Billboard chart history by becoming the first-ever act to score song of the year with the same song, "Lemon," for two years running.

The 28-year-old has evolved into one of Japan's leading artists in recent years -- he even illustrates his own music videos and album covers -- and his ever-growing list of accolades continues to accumulate in 2019.

The record-breaking figures related to his releases show that what draws listeners to his music is the universality of his pop songs that resonate with the climate of the times, not simply because it is trendy or newsworthy.

His long-running hit "Lemon," released in March 2018, sailed past 3 million downloads in September. At the end of the year, it topped four metrics of the Billboard Japan Hot 100 methodology -- downloads, look-ups (the number of times a CD is ripped to a computer), Twitter mentions and video views -- and was named the 2018 song of the year.

The ubiquitous track led the Oricon weekly karaoke ranking consecutively for over a year and a half after its release, and on the Billboard Japan charts, it led the karaoke list for 49 straight weeks after the metric was added to the chart measurement around this time last year. View counts for the music video currently sit at more than 495 million on YouTube, making it the most-viewed music video in Japan to date. As 2019 draws to a close, these results prove that "Lemon" still reigns as the representative song of this year as well.

Why has this song remained so popular for so long? The foremost reason, needless to say, is the power of the song itself. While the track features a distinctive voice sample that grabs listeners by the ear, the melancholy melody possesses strength that endures the passage of time and repeated plays.

The evocative nature of the poetic lyrics also plays a major role. Yonezu is singing about the sorrow of loss and undying love in "Lemon." The theme of this song is death. He has shared in past interviews that he drew from the experience of facing his grandfather's passing to write it. It is not a happy tune, but nobody is exempt from facing the death of a loved one at some point in their lives, so the theme is universal. This is another reason why "Lemon" has become a number that profoundly touches the hearts of so many.

Meanwhile, Yonezu hasn't just been sitting idly on his laurels this past year. From January to March, he traveled to cities throughout Japan for his first arena tour, titled Sekitsui ga opal ni naru koro ("When (one's) spine turns into opal"), which drew 170,000 fans in attendance. The tour also added two dates abroad in Shanghai and Taipei, his first-ever concerts outside of Japan, and the sold-out crowds proved his steadily growing reach.

In June, the hitmaker dropped "Spirits of the Sea," the theme song he wrote for the animated feature film Children of the Sea. Yonezu had been a fan of Daisuke Igarashi's original manga the movie was based on from his teens, so the opportunity was a dream come true. The majestic number features a full orchestra and a "digital choir" choral method, epitomizing his ambitious stance as he continues to update his musical expression.

Furthermore, his latest release called "Uma to Shika" has also become a representative song of 2019. The single released in September has sold 1.1 million units to date, physical and digital combined, leading the Billboard Japan downloads metric for 11 inconsecutive weeks.

While the song has enjoyed commercial success in its own right, it also turned into something of a social phenomenon linked to the 2019 Rugby World Cup that took place in Japan. This number was originally written as the theme of a rugby-themed drama series that depicted the struggles of a company team. It left a lingering impression on viewers, and the song soon became an anthem for rugby itself, used to highlight the excitement of the actual World Cup games.

The reason for this also lies in the power of the song itself. "Uma to Shika" depicts the moments of joy and excitement that arrive after stoic training. Lyrics encouraging athletes before a game and honoring their performance are sung over a dramatic track, which moved actual players including team Japan winger Kenki Fukuoka, who expressed his gratitude to Yonezu on social media. The song was played in the stadium after the team's games during the World Cup -- which saw team Japan reach the knock-out stage for the first time -- and the song symbolized the birth of a new anthem in both Yonezu's career and the Japanese music scene.

On top of these achievements, Yonezu also enjoyed a successful year as the producer of other growing acts. For example, Japanese actor Masaki Suda established himself as a singer this year with hit songs including "Machigaisagashi," which Yonezu wrote and produced.

Another breakout act was Foorin, a group of five kids who performed the Yonezu-produced "Paprika," which won the hearts of young children all over the country with its catchy melody and danceable choreography by Tomohiko Tsujimoto and Koharu Sugawara.

Created for NHK as part of its 2020 Tokyo Olympics supporters' project, the tune was released in July and gradually gained traction through the national broadcasting organization's educational channel and official events around the country.

The original music video introducing the choreography has been viewed over 147 million times on YouTube to date, and now the song has become so familiar to little kids around the country that just hearing the intro can put smiles on their faces and get them up and dancing.

In September, Yonezu released a music video of his own rendition, giving the song a sparser, more nostalgic arrangement. The new video promptly sailed past 10 million views, faster than any of his previous releases, and popularized the song to a wider audience.

In the spirit of the Olympic games, the theme of "Paprika" is "to broaden the circle (of goodwill) from kids in Japan to kids in the world." In December, an English-language version of the J-pop hit will be released, performed by a new group of native English-speaking kids called Foorin team E.

The hitmaker faced a new challenge, having never written a song completely in English before, but the children's song's catchiness and universality remained intact, regardless of the language. "I want the song to be a celebration for children," he said of his creation, and his hope will likely spread throughout the world, transcending borders and time.