Trying to follow the logic behind how K'ang Hsi dealt with Obai (in DOMD).

[Ken Cheng]

K'ang Hsi was the Emperor of China. At his discretion and on his authority, he could order Obai's execution without explanation.

K'ang Hsi didn't do so, however, because of the realpolitik that underlay the situation. Though Obai menaced him and contravened the Emperor's authority, K'ang Hsi knew that he would pay a heavy political price if he ordered Obai's arrest and execution seemingly without reason. Obai was popular with the people as a military hero, and he was also popular with many of his colleagues in the Qing imperial court. Executing him would have undermined the bureaucracy and the people's faith and trust in K'ang Hsi.

So K'ang Hsi developed an alternative plan (in DOMD): he would use Wai Siu Bo and a gang of wrestlers to murder Obai for him.

Query: how would this be any better? Either way, the news would go out that the Emperor caused the violent death of Obai. Would it be any different whether Obai was formally executed or killed in the Emperor's gymnasium? Unless the plan was to try to make Obai's death in the gym look like an unfortunate accident rather than murder?

[Doc Kwok]

K'ang Hsi was the Emperor of China. At his discretion and on his authority, he could order Obai's execution without explanation.

K'ang Hsi didn't do so, however, because of the realpolitik that underlay the situation. Though Obai menaced him and contravened the Emperor's authority, K'ang Hsi knew that he would pay a heavy political price if he ordered Obai's arrest and execution seemingly without reason. Obai was popular with the people as a military hero, and he was also popular with many of his colleagues in the Qing imperial court. Executing him would have undermined the bureaucracy and the people's faith and trust in K'ang Hsi.

Oboi was hated by the general public and by practically everyone outside of his own banner due to his violent and overbearing ways. The immediate problem was his influence - practically all the imperial guards in the palace were in his pocket, so if KX tried to have him publicly arrested/executed, chances were that he would immediately rebel and have KX and his family slaughtered instead. Then there was the memory of KX's father - Oboi was nominated as a regent by the Shunzhi emperor, so ordering him executed would look unfilial and throw the judgement of his father in question.

So K'ang Hsi developed an alternative plan (in DOMD): he would use Wai Siu Bo and a gang of wrestlers to murder Obai for him.

Query: how would this be any better? Either way, the news would go out that the Emperor caused the violent death of Obai. Would it be any different whether Obai was formally executed or killed in the Emperor's gymnasium? Unless the plan was to try to make Obai's death in the gym look like an unfortunate accident rather than murder?

The idea was probably to capture Oboi quietly by himself, away from all his followers, then swiftly deal with all his followers before they had any idea of what was happening. As it happens, it inadvertently went down even better than planned - Oboi literally tore apart all but a handful of the eunuchs, and assaulted Kangxi himself. That way, it looks like Oboi was the instigator rather than Kangxi, with the shocking state of the room as compelling evidence, and no-one left alive was saying otherwise.

The penalty for attempting to assassinate the emperor was the nine exterminations, with the assassin himself undergoing the Lingchi execution, so this allowed Kangxi plenty of justified leeway in way of punishing Oboi and his minions. As it was, he was relatively merciful, only executing Oboi's closest henchmen, and sentencing Oboi to life imprisonment (figuring that he would die of his wounds anyway).

[Ken Cheng]

One additional question, if I may: your response indicated that Obai was hated by the people. I'm sure the Han population hated and feared him, but would he not have been a military hero among the Manchurian population?

[Mandred Skavenslayer]

For one Kangxi before hand had done a lot of ground work, ie having his own maternal uncle take command of the Imperial Guard, thus mitigating the threat of an immediate military reprisal.
Second Oboi's virtual dictatorship and favoritism towards his own Banner had made him very unpopular with the other Manchu Banner men, which along with his execution of Suksaha gave him a mortal enemy in the Plain White Banner.
Also, the main aim of the plan was not to kill Oboi but to subdue him and then have him quietly done away with in prison, thus Kangxi can avoid the stigma of having executed an important noble.

[Ken Cheng]

@Doc Kwok: I managed to find a way to restore your original response!