A South Korean court’s decision to release President Yoon Suk-yeol from detention has ignited debate over whether detention periods should be calculated by hours or full days—an issue that could reshape the country’s legal system.
Prosecutors have traditionally measured detention in calendar days, but the court adopted an hour-based approach, significantly reducing Yoon’s time in custody. If courts continue to apply this method, it could lead to major changes in pretrial detention rules and other legal proceedings.
A fundamental principle in criminal justice is in dubio pro reo, or “when in doubt, rule in favor of the accused.” Judge Jee Kui-youn of the Seoul Central District Court appeared to apply this principle when he ruled that Yoon’s detention should be measured in hours rather than full days. This shift led to a discrepancy in how the prosecution and court calculated Yoon’s time in custody.
The issue arose as Yoon’s request for detention cancellation was processed between the court and the prosecution. From 5:46 p.m. on Jan. 17 to 2:53 a.m. on Jan. 19, the case remained under review for 33 hours and 7 minutes. Under the prosecution’s long-standing day-based calculation, this would have extended the detention period by three full days. However, using the hour-based method, the extension was only 33 hours—effectively cutting nearly two days from Yoon’s time in custody.
“From a defendant’s perspective, even a minute or a second less in detention is preferable, so they would naturally favor the hour-based approach over the day-based one,” a defense lawyer said.
Judge Jee also noted that the hour-based system could sometimes work in favor of prosecutors. If the time spent transferring case documents between the court and prosecution is counted in hours rather than full days, prosecutors could extend their ability to keep suspects in custody. For instance, if a detention review request is filed at 2 p.m. on July 1 and returned at 1 p.m. on July 2, a day-based calculation would count two days, while an hour-based calculation would count only 23 hours, preserving more detention time.
The hour-based approach has not yet been established as a binding precedent. Supreme Court Justice Chun Dae-yup, who heads South Korea’s National Court Administration, said on March 12 that there is no settled case law on how detention periods should be calculated.
“It is unclear whether this decision will be upheld in higher courts,” Chun said. “The ruling must undergo further judicial review.” However, he added that “court decisions should be respected until overturned by a higher court.”
On March 11, the Supreme Prosecutors’ Office instructed lower prosecutors’ offices to continue applying the traditional day-based method until a final ruling is made by the Supreme Court. “All prosecution offices should maintain the existing approach until a definitive ruling is issued,” it said, advising prosecutors to consult the agency’s criminal policy division in cases where disputes arise.
A former prosecutor-turned-lawyer noted that neither the Supreme Court nor the prosecution has established a definitive standard. “Prosecutors will likely opt for the method that minimizes legal risks—whether that means using the day-based or hour-based calculation, depending on the case,” he said.
Defense attorneys specializing in criminal law say they are already receiving inquiries from detained clients about whether they could apply for release based on the hour-based calculation. “This ruling is an exceptional case, and it is difficult to use it as a precedent,” one lawyer said.
A judge based in Seoul noted that if courts officially adopt the hour-based calculation, they would need to meticulously track and verify detention periods for each case. “This could lead to outcomes more favorable to defendants while increasing the burden on prosecutors,” he said.
