'Playing the man, not the ball'
In football, it would be known as playing the man, not the ball. Away from the beautiful game, it might be considered to be an "ad hominem" approach.
Either way, it was plainly Johann Lamont's tactic at Holyrood today to sustain a personal attack against First Minister Alex Salmond.
To be fair, the Labour leader was intent on playing both the man and the ball. A form of sliding tackle, if you like.
She pursued, rather vigorously and rather effectively, the issue of rising unemployment and, more precisely, the alleged partial culpability of the FM in that regard.
But she went further - with a direct, structured and undoubtedly planned attack upon the character of Mr Salmond. Not just his policies, not just his politics - but also his person.
She lampooned him as a man who wanted to join the "arc of prosperity" (Iceland, Ireland, Norway). She described him as a man who had graduated from the "Fred Goodwin school of economics".
Was I alone in thinking that her repeated use of the word "man" was notably emphatic, particularly as she was talking about unemployment among women at the time?
Again either way, it was a good performance.
She contrived to be representing the plain-speaking concern of those losing their jobs in Scotland - while, of course, employing a carefully-worked rhetorical structure to underscore her attack on the FM as "ultra-complacent".
And Mr Salmond's response? That he attaches the highest importance to job creation - but that the lack of powers in Scotland to stimulate economic demand hampers his efforts.
Ms Lamont characterised that as "hunt the alibi" which, on the day, was reasonably effective.
Longer term, of course, the people of Scotland will be judging not just a first minister under attack but an alternative economic scenario too.
Mr Salmond noted that Finance Secretary John Swinney had acted strenuously to switch money from revenue to capital, thus boosting investment.
This was, he said, one of Scottish Labour's key demands - while the others had all been aimed at powers presently in UK hands.
He noted further that Labour at Westminster now appeared to be backing the present UK government's economic policy.
Or, as he put it, acting "in cahoots" with the Tories over both the constitution and the economy.
I suspect Mr Salmond may slightly regret his attempt to play down Ms Lamont's contribution as a pseudo-apolitical script written for her by Paul Sinclair, her new media adviser.
In the chamber, that sounded too much like a process issue, with little direct relevance to the matter under discussion. Further, does Mr Salmond not take guidance from advisers?
But the FM undoubtedly finished strongly by listing in considerable detail the initiatives undertaken by his government to tackle unemployment, including among women and the young.
As to the others, Ruth Davidson of the Conservatives pursued the issue of independent Scottish membership of the European Union with, I felt, modest effect on the day.
Willie Rennie, of the Liberal Democrats, fared rather better with a "why oh why" lament about plans for a single police force.
Neither, though, particularly discomfited the FM.