JyNI is a compatibility layer with the goal to enable Jython to use native CPython extensions like NumPy or SciPy. So far it was developed on Linux and some additional effort was spent to let the core part work properly on OSX. In principle the current version of JyNI is workable on POSIX platforms. I propose to create a proper Windows version of JyNI. A fully accurate implementation of this proposal includes to establish workability of all extensions and features that are currently supported on POSIX platforms.