In most Aikido techniques Nage moves into the position in which Uke is standing. This has two powerful advantages. The first is that this causes Nage's hips to gently touch Uke's hips during the Off Balance. This touch is so light that it is not noticed but it destroys Uke's balance making the throw effortless magic. The second advantage is that when many attackers are coming at once Nage moves through one of the attackers rather than going into the dangerous zone between two attackers.
When doing Irimi as in Kokyu Nage, Nage's lead foot slides beside Uke's trailing foot. This causes Nage's lead leg to gently touch Uke's lead leg causing Uke to lose balance and fall.