A hearing is held at the main courtroom of the Constitutional Court in Seoul, Dec. 10. Yonhap

A justice known for his conservative stance will lead the Constitutional Court's review of President Yoon Suk Yeol's impeachment motion.

The court said, Monday, Justice Cheong Hyung-sik was selected as the presiding judge of the case. The selection was made through a random computer draw, it added.

Cheong was named by Yoon in December last year. According to the law of the nine-member court, three justices are named by the president, three by the Supreme Court chief justice and three by the National Assembly.

The court initially said that it would not disclose the identity of the presiding justice of the high-profile case, in accordance with its non-disclosure principle. But the identity was made public later in the day.

Regarding the disclosure, the court said in a message to reporters, "All the justices are engaged in the hearings, so the presiding justice does not affect the speed or direction of the decision."

Justice Cheong Hyung-sik sits at the main courtroom of the Constitutional Court in Seoul, Dec. 10. Yonhap

First preparatory hearing set for Dec. 27

The court also decided to hold the first preparatory hearing at 2 p.m. on Dec. 27. The decision was made during a meeting led by Acting Chief Justice Moon Hyung-bae, with all six current justices attending. The court is currently operating with only six justices instead of the full nine, as the replacements for the retired three have yet to be appointed.

The preparatory hearing is a session held before public argument hearings, designed to clarify key issues of the trial, discuss the review of evidence, and determine the selection of witnesses in advance.

"During this hearing, investigative records from the prosecution, police and other authorities will be obtained as early as possible," a court spokesperson said.

The impeachment trial of Yoon has moved into the preparatory stage of the Constitutional Court's process.

The court began the trial procedures on Saturday after receiving the impeachment document from the National Assembly. On Sunday, the justices reviewed the case from their residences.

A man walks toward the front gate of the Constitutional Court in Seoul, Monday. Yonhap

The court also said it notified the case to the defendant — Yoon — and is currently requesting the submission of responses from him. Ahead of the impeachment trial, Yoon is said to have finalized his legal defense team. The team will be led by Kim Hong-il, former chair of the Korea Communications Commission.

The court plans to proceed with the impeachment trial as swiftly as possible, the spokesperson said.

The public hearing sessions for the impeachment trial require the participation of both parties. Rep. Jung Chung-rae of the Democratic Party of Korea (DPK), chair of the National Assembly's Legislative and Judiciary Committee, will serve as the impeachment prosecutor, while Yoon, the defendant, is also required to appear.

The number of witnesses selected for the trial is expected to impact the timeline of the impeachment process. However, it is widely anticipated that the court will reach its final ruling by the end of April.

This is due to the planned retirement of two justices — Moon and Justice Lee Mi-son — whose terms will end on April 18. During the impeachment trial of former President Park Geun-hye, the final ruling came out on March 10, 2017, just three days before the retirement of then-acting Chief Justice Lee Jung-mi.

Constitutional Court justices enter the court in central Seoul, Monday. From left are Justices Moon Hyung-bae, Cheong Hyung-sik, Kim Bok-hyeong, Kim Hyung-du, Lee Mi-son and Jung Jung-mi. Yonhap

The problem is that three of the nine seats at the Constitutional Court have been vacant since Oct. 17.

As both the ruling People Power Party and opposition parties nominated their candidates for the National Assembly's share of the justices, and the legislative body plans to quickly complete the appointment process, including confirmation hearings, within this month, the Constitutional Court is expected to fill the empty seats as early as late December.

If at least six justices rule in favor of removing the president, Yoon's impeachment will be confirmed. If this threshold is not met, the case will be dismissed.

The Constitutional Court Act mandates that an impeachment decision be made within 180 days after receiving the case, although this timeline is not legally binding.

In the past two presidential impeachment cases, the proceedings were completed in less than 180 days. The impeachment trial of former President Roh Moo-hyun took 63 days, while that of former President Park Geun-hye was concluded in 91 days.