How nastily manipulative should Falstaff be and how much a forgivable - even lovable - old reprobate? Is Hal cynically calculating or a king-in-waiting whose loyalties are divided between his usurping father, King Henry IV, and his surrogate father, the dissolute Falstaff?
Michael Attenborough's production of Parts 1 and 2 finds the balance superbly, allowing massy Desmond Barrit to be good company as the fat knight but not glossing over his immorality, his cheating, his carelessness about the suffering and death of soldiers and recruits.
Hal, meanwhile, is genuinely fond of Falstaff, to whom he needs to escape before the responsibilities of state become onerous, but he is not deceiving him: kingly authority is already visible in the prince's playfulness.
William Houston has managed to make Hal a rounded, believable character whose qualities will fit him for kingship - something that the RSC's history sequence, This England, allows him to prove in Edward Hall's production of Henry V.
The linking theme, in the first three plays of the sequence, Richard II and the two parts of Henry IV, is best summed up in a line spoken by King Henry: "Uneasy lies the head that wears acrown."
David Troughton, excellent as the conscience-stricken - and by now physically weak - king, winces in pain whenever he puts on the troublesome crown. It is much in evidence on stage, a symbol of power, guilt and fear as Henry IV expresses his anxiety about his successor's suitability. The young Hal dons the crown with an ease his father couldn't dream of and enters in a blaze of light, glamorous, assured and not to be troubled by his erstwhile drinking companions.
Part 2 is the less coherent play but the Shallow and Silence scenes are always a delight. Benjamin Whitrow and Peter Copley enjoy themselves no end as the retired pillars of the establishment recalling, in idyllic Gloucestershire, the "colourful" exploits of their youth among the "bona robas" of the city.
The reconciliation between Hal and his dying father as they sit together leaning against the royal bed is touching in human terms, and augurs well for the monarchy.
Es Devlin's set, with its steep rake from half-way back, serves well to suggest a battlefield (stuck with arrows), Gad's Hill, where the robbery takes place in Part I, and a gilded orchard in Part 2.
Tickets: 020 7638 8891. Until April 18. Henry V previews until March 22. Performances until April 21