Adam Thirlwell's contention that 'Jewish is always half-Jewish' is provocative. Whilst themes of not belonging are central to much Jewish writing, Thirlwell's claim effectively dismisses the idea that there could ever be a wholly Jewish identity. To the extent that all identities are arguably provisional, constructed and contingent, this might be the case. However, there is a danger that Thirlwell's contention is not entirely playful. The implications of such a manoeuvre are explored in Andrew Sanger's novel, The J-Word (2009) and Mark Glanville's memoir, The Goldberg Variations (2004), which, in different ways, both reflect on the challenges of inchoate identities. This article looks at the ways in which these texts problematize a sense of blurred boundaries in terms of (half-)Jewishness. It will go on to argue, however, that whereas some contemporary British Jewish writers demonstrate a rather fraught sense of identification, others are less attached to a singular or even dual sense of defining identity. As the twenty-first century unfolds, British Jewishness is increasingly figured as a matrix of connections that form ever more imbricated ways of belonging.