In underworld novels, there would usually be some special situations where one had to distinguish between their own people. Here are some possible methods: [1. Observe clothing and equipment: When fighting with your own people, you will usually wear different clothing and equipment.] For example, his own people might wear high-end clothes and shoes while his opponents might wear worn-out clothes and slippers. In addition, their own people might use different weapons and tools such as knives, guns, sticks, etc. By observing these details, he could distinguish his own people from other opponents. 2. Observe your speech and mannerisms: When fighting with your own people, there will usually be a tense atmosphere and you will be more cautious in your speech and mannerisms. If the other party's speech and behavior showed that he was calm and collected, or showed that he agreed with and supported him, then he might be one of them. On the other hand, if the other party was flustered, evasive, or suspicious, it could be another opponent. 3. Observing behavior patterns: When fighting with your own people, there will usually be a series of behavior patterns. For example, their own people might attack, threaten, provoke, or show some kind of tacit understanding and cooperation. If the other party's behavior showed obvious hostility, then it might be one of their own. On the other hand, if the other party's behavior pattern was relatively normal or showed some abnormal behavior, then it might be another opponent. It should be noted that the above methods could not completely guarantee the identification of their own people because the situation in underworld novels was very complicated. Sometimes, it was difficult to distinguish their own people through simple observation and behavior patterns.