Why did the Tokugawa shogunate keep Japan isolated from 1603 until 1853?

http://www.google.com/search?rlz=1C1GGGE_enUS379US379&aq=f&gcx=w&sourceid=chrome&ie=UTF-8&q=Tokugawa+shogunate

Read carefully.

In general, the Japanese shoguns believed that their country and people were superior to others and did not need anything from outsiders.

http://en.wikipedia.org/wiki/Sakoku#Rationale

My bulldozer says the answer is this, It is generally regarded that the shogunate imposed and enforced the sakoku policy (isolation)under which no foreigner or Japanese could enter or leave the country on penalty of death.

this was done in order to remove the colonial and religious influence of primarily Spain and Portugal, which was perceived as posing a threat to the stability of the shogunate and to peace in the archipelago. The increasing number of Catholic Christian converts in southern Japan was a significant element of that which was seen as a threat.
Your welcome hohpe this helps,

The Tokugawa shogunate, also known as the Edo period, implemented a policy of sakoku, which means "closed country" or "isolation." There were several reasons why the shogunate decided to isolate Japan during this period.

1. Consolidation of Power: The Tokugawa shogunate aimed to consolidate its political control over Japan by centralizing power in the hands of the samurai class. Maintaining isolation helped to prevent rival daimyo (feudal lords) from gaining support or forming alliances with foreign powers.

2. Stability and Social Control: The shogunate wanted to maintain internal stability and control over the Japanese society. By isolating the country, they were able to minimize foreign influence, control cultural and ideological developments, and reduce the chances of outside ideas threatening their authority.

3. Fear of Colonialism: The Tokugawa shogunate was aware of the aggressive imperialism and colonialism taking place in neighboring countries, such as European powers expanding their influence in Asia. Isolation was seen as a way to safeguard Japan from potential invasion or colonization by foreign powers.

4. Protection of Traditional Culture: The shogunate sought to preserve traditional Japanese culture, values, and customs. They were concerned that external influences could erode their unique way of life, and by restricting contact with the outside world, they aimed to protect their traditions and identity.

To understand the reasons behind the Tokugawa shogunate's isolationist policy, it is necessary to study Japanese history during that period, including the political context, social structure, and international factors. By examining primary sources, secondary literature, and scholarly interpretations, we gain a comprehensive understanding of why the shogunate made the decision to keep Japan isolated for more than two centuries.