SEOUL (The Korea Herald/ ANN) - As of Sunday (July 22), Korean pop giants such as Twice, Black Pink, Apink, Mamamoo and BTS had claimed leading spots on the charts of most music streaming websites in South Korea. But controversy has arisen as a single from little-known musician Shaun, titled Way Back Home, took top spot at Melon, Genie and other major South Korean charts

Shaun is a singer who also plays synthesiser for rock band the Koxx, which debuted in 2009. His unexpected surge on the charts has sparked suspicion over chart manipulation.

"When a little-known musician tops the charts, there is usually some explanation behind it. But in Shaun's case, there wasn't. The controversy is from him taking a No. 1 spot (between noon and dawn)," said culture critic Kim Jak-ga on an MBC radio show.

There have been several cases in South Korea where a relative newcomer has been suspected of manipulating his or her place on the music rankings by inflating purchases online. (Last month, girl group Momoland was cleared of similar accusations of chart-rigging.)

Record companies and artists are suspected to buy in bulk from 1am to 7am, when there are fewer users and even a relatively low number of sales can affect the charts.

As music streaming websites list charts right up top, taking the No. 1 spot boosts visibility and can help further boost sales. The process is called "sajaegi," which literally means "buy and stock".

Buying or having related personnel purchase copies of a certain musical record to manipulate sales numbers is punishable by law in the country.

In order to prevent such practices, a collection of music streaming and sales websites announced earlier in the month that they would freeze chart rankings between from 1am to 7am.

Shaun's tune took the top spot at midnight, right before the chart freeze started, and so stayed on top until the next morning.

The artist insists on his innocence, and on Friday requested a police investigation into the case. He also filed charges on several citizens for spreading rumours about him manipulating the charts.

"I hope that no one gets hurt while the truth is uncovered...I want to say I'm sorry (to the fans) by showing them hard evidence as fast as I can, but it is such a rough road until the truth is revealed," Shaun said via his Instagram page on Sunday.

Shaun's agency Dctom Entertainment has said his surge in the charts was thanks to its viral marketing strategy. It did not elaborate on what that may have entailed.

In the music industry, songs often hit their highest places on the charts immediately after release. It is also not rare for songs to climb the rankings over time, sometimes months after the initial release.

EXID is a household name in K-pop now, but the girl group was relatively obscure in 2014, its third year together, when a video of member Hani performing the song Up&Down went viral.

Up&Down had created virtually no buzz upon its August release but the video of Hani spread via social media, creating such a buzz that the band finally surged on local charts four months later. It even landed its first-ever No. 1 spot on a TV ranking programme on a major broadcaster.

Pop culture watchers point out, however, that before such dark horses appear on the charts, there is usually buzz about the artists online and offline. In contrast, there was little such buzz before Shaun topped the charts.

Park Jin-young, founder of JYP Entertainment, said he plans to request the Ministry of Culture, Sports and Tourism to investigate, with a view to future prosecution.

Some musicians have pointed out that often the very fact that an artist topped the charts sparks a buzz, leading them to affect the charts in any way possible.

"Charts should reflect the state (of music world), but it is actually the charts that create such state. This causes artists to chart using whatever means necessary," said singer and producer Yoon Jong-shin.

With the real-time charts under dispute, those in music circles are suggesting a switch to weekly charts.