Author of the Inspector Morse series, Colin Dexter, appears in a cameo. When Morse takes Alex Robson to hospital to visit her Aunt Jane, a doctor, portrayed by Dexter, is standing to the left, reviewing a chart, which he hangs up at the foot of the neighboring bed and walks out of the scene.
The first Inspector Morse episode not to be based on a Colin Dexter story
The title would appear to be a play on the homonyms "sun" and "son", with the plot revolving around a Japanese man (i.e., from the Land of the Rising Sun), and the intended vengeance of one father's son upon another father's son for wrongs committed by the latter father upon the former in the distant past.
The Nissan car advertisement from 1987 that Lewis has on in the background features the voice of Tim Healy who started alongside Kevin Whately in Auf Wiedersehen, Pet (1983).
Robert Lang, who played Superintendent Dewar, later starred with John Thaw in Kavanagh Q.C. as Mr. Justice Benson.