A boy whose father murdered his mother should live with his paternal relatives in England - not his maternal family in China, a family court judge has ruled.
Mr Justice Holman said the boy was a British citizen and grew up in England. He said a move to China would involve "huge upheaval".
Detail of the case has emerged in a written ruling on the case following a hearing in a family court in Birmingham.
The judge said the boy - now six - could not be named.
Mr Justice Holman said the boy's father brutally murdered his mother in a "very premeditated and carefully planned attack" and was serving a life sentence.
The judge said the boy was placed with foster parents following the killing.
He said social services staff asked him to make decisions about the boy's long-term future.
The boy's mother was Chinese and his father a British citizen of Chinese ethnicity.
He said the boy could not remain a foster child and said the options were a move to a couple related to his father in England or a move to his maternal grandparents in China.
"Within the space of a few days (the boy) effectively lost both his parents," said Mr Justice Holman in his ruling.
"His mother was dead. His father was incarcerated, and (the boy) has not seen him since."
The judge added: "As soon as his father was arrested, (the boy) was placed with sensitive and caring foster parents who continue to care for him with devotion and skill.
"But he should not remain a foster child. The issue I have to decide is whether he should now move to live permanently with his maternal grandparents, who live in a city in China, or with his father's (relatives)."
Mr Justice Holman said a move to paternal relatives in England was "clearly" in the boy's overall best interests.
"The strength of the case of the grandparents is that they are indeed his closest living maternal relatives and a last living link to his mother," said the judge.
"That does not, in my view, outweigh the huge upheaval that it would involve for him now to move to live in China."
He said the boy had suffered "an immense emotional and psychological shock already" and a move to a new home needed to be "as smooth and uncomplicated" as possible.
"The issue of great concern in relation to the (father's relatives) is their relationship to the perpetrator father. In many cases, this might rule them out," said the judge.
"I am quite satisfied that this particular aunt and uncle have completely satisfied themselves of the father's guilt. They do not in any way whatsoever attribute responsibility to the mother.
"They will not give to (the boy) a skewed version of events as he grows up, and indeed they are better placed than the grandparents in this case to enable (the boy) to grow up with a fair, true and proper understanding of his tragic history.
"In all other respects, a move to (the father's relatives) can only be very positive for (the boy).
"He knows them and their children well. He has a considerable attachment to them already. There are no reservations about their parenting capacities or material security. They have arranged, and can provide, a relatively seamless move to a school not markedly dissimilar to his present one."
Mr Justice Holman outlined detail of the murder in his ruling - although he did not identify anyone involved.
He said the relationship had been "conflictual". They had divorced and each had former new "partnerships".
The judge said the little boy had lived with his mother for the last year of her life - although he had contact with his father.
He said the trigger for the killing seemed to have been a proposal from the woman's solicitor that the man should have less contact with the boy.
Mr Justice Holman said the man continued to protest his "complete innocence".
The judge said everyone involved agreed that the little boy should stay in contact with his maternal grandparents in China.
But he doubted whether the little boy would be able to see his father for many years.
"It was explained to (the boy) in age-appropriate terms that his father was the person who had killed his mother," said Mr Justice Holman.
"(The boy) said that he knew that already.
"But the father continues to maintain his innocence and (for that reason, understandably) declines and is unable to express any apology to (the boy) for what he did.
"When (the boy) is much older he may wish to see his father and confront him about his guilt, but at his present age and fragile state of emotional recovery it is impossible to visualise that any meeting can take place between (the boy) and his father unless and until the father displays genuine acceptance of the verdict and appropriate remorse."