Emergence: The elusive side of war ■ Liu Haiye, Zhang Yang, and Zhang Defeng's introduction Emergence is one of the fundamental characteristics of complex systems. War, as a typical complex system, its emergence is the result of the continuous adaptation, interaction, confrontation, and self-organization of various elements of war. The emergence of complex systems in war can make the process of war difficult to control and the outcome of war uncertain, which requires careful research and application. Recognizing the emergence of complex systems in war, the emergence of complex systems in war originates from the adaptive and massive interaction of various elements of war. According to the theory of complexity science, individuals within complex systems possess adaptive, interactive, and self-organizing abilities. It is through continuous adaptation and interaction that the collective behavior of a large number of individuals self-organizes and evolves into complex, constantly changing, and unpredictable behavior patterns, and emerges with overall properties. Simple behaviors such as foraging by animal colonies of bees and ants, and more complex behaviors such as war activities in human society, all follow the basic pattern of emergence, as if dominated by an invisible pair of hands. In biology, when a bee discovers a large flower cluster that can gather honey, it will return to the hive and perform a "figure eight dance". Its companions can accurately determine the direction and distance of the flower cluster based on the dance, resulting in a unified swarm feeding behavior as a whole. The human brain can be seen as a network of billions of interconnected neurons, each of which, although of varying sizes, has similar functions, leading to the emergence of superb intelligence and self-awareness in humans as a whole. In future joint operations, the elements involved will become increasingly diverse, diverse, and complex. As the combat process evolves, the interaction between various elements will not increase linearly and regularly, and it is highly likely to be a non-linear exponential explosive growth. This will lead to the emergence of complex systems in warfare becoming more frequent and unexpected. The emergence of complex systems in warfare can occur anytime, anywhere, and is difficult to predict. 'At any time' refers to the phenomenon of 'black swans' that occur when the timing of the emergence is difficult to predict and may occur' unexpectedly and reasonably '; 'Anywhere' refers to the difficulty in controlling the emerging combat domains, which may result in a 'cross domain effect' of 'force integration and effect fusion'. Due to the fact that the evolution process of complex systems in warfare is a process of massive interaction of various factors, transitioning from high-dimensional to low-dimensional, and possessing strong randomness and uncertainty, various factors can change both themselves and the environment. When and where "quantitative change" on the battlefield transforms into "qualitative change" is not something that commanders can accurately predict with wishful thinking before the war. The "toilet effect" in the Kosovo War is very worthy of analysis from the perspective of the emergence of complex war systems. In March 1999, after the outbreak of the Kosovo War, NATO launched key air strikes on important military targets such as the Federal Command Center and air defense systems, but the results were minimal, and the resistance of the people of the Federal Republic of Yugoslavia did not weaken. Since mid April, NATO has changed its combat strategy to include civilian infrastructure such as power and water systems in the scope of air strikes. Afterwards, the resistance of ordinary people in the Confederacy began to weaken, and they even frequently took to the streets to protest against the ruling authorities. The transformation of the resistance will of the people of the Confederacy from strong to weak has at one point caused a hundred external factors