Which Market is the leader?

Well, personally i prefer not to keep track of stocks/markets on a daily basis. I believe in remaining ivested with a company for atleast 2-3 years unless conditions have changed adversely for the company business which makes little sense in holding onto its stock/bonds. Anyway, almost everyday we come across a common news such as "Markets to open following global cues" or "Today market will open taking cues from the yesterdays NASDAQ/DOW closing figures". ..etc. So i believed it is fair to assume for example that the TOPIX or the NIKKEI index in Japan will perform in close co-relation with the previous day close for US indices.

So recently, i have been checking the US market moves/sentiment late Tokyo evening time before going to bed (bad habit!). This way i thought i will get a fair idea of what can be expected of the Tokyo indices the next morning. But last week, i was talking with a colleague from NY who had visited our Tokyo office for business. and he commented "You know we guys (US Market) are very much dependent on the performance of the Tokyo market. Our indices perform based on global cues (Tokyo in his case!)". While until then i was thinking the exact opposite. Apparantely, the colleague checks on NIKKEI index figure before he goes to bed NY time ! Chicken First/Egg first situation..

So who is the Market leader in this case? Tokyo (Early to rise) or NY(Late to Bed)? Well, i think both. Since the end values are affected by the intra-day price movements which depend on economic, political events and other updates during the business hours thereby affecting the markets in the other parts of the Globe (next morning). Also, advances in technology have made information to be available instantly and simultaneously to maket makers all over the globe thereby reducing the 'time-lag' factor. i.e. leaving very little scope for arbitragers to earn any profit !