W-39 (Wrzesieñ, i.e. September 1939) system rules is a Polish wargame family. These games represent battles taking place during the invasion of Poland, 1939. The scale is battalion-regiment.
They were first published by Dragon and now by Taktyka i Strategia.
Expansions in Taktyka i Strategia magazine
No.7: Swientokrzyskie Mountain 1939
No.8: Wisla 1939
No.13: Wielkopolska 1939
No.16: Mlawa 1939 (I) - republished in a box
No.17: Mlawa 1939 (II) - republished in a box
No.29: Lądowa Obrona Wybrzeża (Land Coastal Command) 1939
No.34: Tomaszow Mazowiecki 1939
No.36: San 1939
No.40: Mokra 1939 - see video for english edition view
No.41: Sochaczew 1939