This paper aims to explain the observation (not previously reported) that -wa obviates Negative Island effects in Japanese degree questions. The explanation offered ties this obviation to epistemic implications associated with -wa, deriving the latter in a (Neo-)Gricean framework. The explanation relies on Fox & Hackl's (2006) view that Negative Islands in degree questions are due to the necessary failure of a Maximality Presupposition, but it abandons their proposal that such presuppositions must be calculated under the assumption that scales of degrees are invariably dense.