Chinese foreign policy is an enigma wrapped in a mystery. There can only be theories as to why China has 40-strong military presence 15 kilometres into the Indian claim area on the eastern Ladakh area. Some theories:
1. Same old: There is a long pattern of intrusions by both sides into the no man's land between the two Lines of Actual Control - itself a fluid concept. This could be the latest round in this long-standing practice. But it has been heightened by a much stronger media spotlight. There has also been a policy of much tougher responses to such intrusions by New Delhi in the past two years.
2. Road block: Since the 2008 to 2010 problem period with China, India has been ramping up its border infrastructure. This is making up for years of neglect by India. But Chinese analysts have long argued their superior roads airfields and bunkers on the border will ensure they will win any future conflict.
New Delhi has noted Beijing often challenges Indian infrastructure building. The eastern Ladakh area has seen new roads in the past year - India used to have to airlift vehicles and supplies there. It is noticeable China has complained in this crisis that Indian building eas changing the status quo.
3. PLA plan: There is some surprise that the intrusion took place just weeks before Premier Li Keqiang's visit to India. The People's Liberation Army often runs a quasi-independent foreign policy and may be trying to send a signal to Li that the new leadership should not take a soft line on India - or at least the border. But Beijing has kept a tight leash on its own media regarding the incident, indicating it doesn't want this to get out of hand. This would be consistent with an intra-leadership struggle.