In an office building in Beijing's Shijingshan district, a special "school" is in full swing, with nearly 200 human teachers and 100 humanoid robot students.

The instructors wear headsets, hold control levers and move slowly, while nearby 1.66-meter-tall humanoid robots mirror their motions. The curriculum is relentlessly mundane. The students repeat everyday tasks such as taking a medicine bottle from a cabinet, carrying goods in a factory, sorting parcels on a conveyor belt, and leafing through office files.

The campus is China's largest humanoid robot data-training center, co-built by the Shijingshan district government and Lejoin Intelligence (Shenzhen) Co, or Leju Robotics. The training areas reproduce factory and household scenes at full scale, with every detail faithfully replicating real working conditions.

Wang Qiang, technical director of Leju Robotics' embodied training center, said the facility has built 16 detailed real-world scenarios spanning industrial manufacturing, smart homes, eldercare services and 5G integration.

Sometimes instructors adjust the lighting, place obstacles in front of a cup or swap its contents so robots learn to handle a variety of situations. Depending on the difficulty of a task, a single data record can take from seconds to minutes.

Occasionally, a robot's hand slips and a cup falls. Wang said such failure data is vital as robots must learn not only what is correct, but also what is wrong.

Zhang Yusong, one of the trainers, said the job does not require a high level of education. A background in mechanics or computers helps, as does physical stamina, since the work involves repeating the same movements many times. After one or two days of training for the job, a teacher can work independently. The training period for a mature employee is about one month.

Zhang said training robots can be like teaching a toddler: trial and error, demonstration and correction. No amount of explaining can substitute for the repetitive process of the robots learning how to reach, grasp and balance in a world that does not pause for mistakes.

Experts generally agree that before humanoid robots can be widely deployed in real-world settings, they must first attend "vocational schools" as a necessary step before they enter society with a functioning "brain".

Engineers often describe humanoid robots as having three layers: a "brain", responsible for perception and decision-making; a "cerebellum", which manages motion control and coordination; and a "body", the physical frame equipped with motors, joints and sensors.

Consider a seemingly simple task such as fetching a glass of water. The brain must break the command into a cascade of judgments. What qualifies as a cup? Where should it be grasped? Where is the water source? How much is enough?

The cerebellum then translates those decisions into precise signals for dozens of joints, which decide how far, how fast, and how to maintain balance. Walking, grasping, pouring — each action depends on continuous, real-time calibration.