Waffledynamics said:
It appears the defenses in the gray zone of Northern Kharkiv were not very robust for some reason.
It is much easier to prepare for significant defensive operations to take advantage of the terrain, positioning troops and weapons systems at appropriate locations for the utility of them, designated the priority of work or tasks, develop obstacles, locations for maintenance and essential services, covering dead spots, set up supply points and routes, tie in units together to create a comprehensive plan, establish good communication and command and control. A mobile defense will be significantly more complicated. One of the US Principles of War is Simplicity.
I would like to know what the terrain looks like North of the city. That will most likely help determine how the Ukrainians will fight. Are there hills, flat land, forests, natural obstacles like rivers?
Large units going on the offense is ten times more difficult and complex than going on the defense. Therefore, I don't have confidence the Russians can quickly execute decisive offensive operations to take the city. In general, the soldiers are not trained well, the generals are not good, and their logistics to support can suck, and centralized decision making will most likely result in an army executing plodding operations.
For those who say I steal from other sources, I stole and plagiarized my narratives from:
FM 3-0 Operations (army.mil)