You don't know what you are talking about, most of the VKT where quiet for example Taipale and most was covered by impassible river, making Tail-Ihantala the best point to breach the line as was shown during the winter war and during the Finnish liberation of Karelia 1941. This home made claim of you that "Battles happened along all VKT line and there are numerous sources about that." Shows that you lack basic knowledge and are not fit to edit this article on facts.