Lotte founder Shin Kyuk-ho, 95, was admitted to Seoul National University Hospital on Monday for a mental competency evaluation, the results of which will play a pivotal role in his sons’ battle over control of the Lotte corporate empire.

The evaluation is a part of the ongoing suit brought by Shin’s younger sister Shin Jung-sook last December, which claimed that Shin Kyuk-ho’s deteriorating mental state required him to have a legal guardian.

The outcome of the evaluation will have considerable sway over the public squabble between Shin Kyuk-ho two sons – Shin Dong-joo and Shin Dong-bin.

The older brother Shin Dong-joo, who had previously controlled Lotte’s Japanese operations, was removed from his post while Shin Dong-bin was promoted to co-CEO of Lotte Holdings in Japan.

Last July, founder Shin Kyuk-ho suddenly dismissed six board members of Lotte Holdings in Japan, including Shin Dong-bin. The move was ostensibly orchestrated by Shin Dong-joo, who had come back into his father’s favor.

Returning fire, Shin Dong-bin dismissed his father at an emergency board meeting, saying that the senior Shin Kyuk-ho’s unilateral actions were void as they did not have board support.

Although Shin Dong-bin currently holds support of shareholders in both Korea and Japan, Shin Dong-joo continues to claim that he has been named the legitimate successor by the senior Shin Kyuk-ho.

Shin Dong-bin claims that his father cannot name an heir because he has grown mentally incompetent with age. The mental evaluation of Shin Kyuk-ho that begins Monday will present evidence for or against that claim.

Shin Kyuk-ho was accompanied to the evaluation by his elder son. In the face of opposition from the Lotte founder and Shin Dong-joo, it is unlikely that Shin Dong-bin will visit the hospital to see his father.

By Won Ho-jung (hjwon@heraldcorp.com)