This paper introduces the idea of data sharing strategy based on a conversion service, not on a sharing application, scheme, or ontology, that are dominant in proposals for language documentation. Although these three methods have been basic tactics for sharing corpora, they have a conceptual flaw in terms of descriptive linguistics. In this paper we report the results of a previous project - the LingDy project, and propose a basic concept for corpus sharing strategy to support personal diachronic data sharing. This paper is a revised version of a handout at JADH2012, so readers should be careful that this content is based on results at the time of 2012.