It is true that the army of the Northern Song Dynasty was relatively poor in combat effectiveness and could not compete with the army of the Jin Dynasty. This is mainly due to several reasons:
First of all, there were serious institutional problems in the Northern Song army. The Northern Song Dynasty implemented a conscription system, which made the army full of a large number of old, weak, sick and disabled, and had low combat effectiveness. At the same time, there was still corruption in the army of the Northern Song Dynasty, and the generals often paid the highest salaries, resulting in a lack of training and equipment for the soldiers, and the combat effectiveness further declined.
Second, the Northern Song army lacked unified command and dispatch. During the Northern Song Dynasty, the army was mainly composed of the first forbidden army and the local box army, and the first forbidden army belonged to different generals and departments, which led to confusion in command and could not form effective combat effectiveness. In addition, there were also strife and internal contradictions among generals in the Northern Song Dynasty army, which also seriously affected the combat effectiveness of the army.
Finally, the technology and equipment of the Northern Song army were relatively backward. Compared with the Jin Dynasty, the Northern Song Dynasty's military technology and equipment level was low, and it could not compete with the advanced ** and tactics of the Jin Dynasty. This put the Northern Song army at a disadvantage in battle.
To sum up, the army of the Northern Song Dynasty was indeed inferior in combat effectiveness and could not compete with the army of the Jin Dynasty. This is mainly due to a combination of institutional problems, command and control problems, and backward technology and equipment.