Comapny Shareholders Equity.

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Increase in capital surplus in case of applying certain practices.

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Multiplying factor for Purchase Price.

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Number of share acquisition rights issued to employees.

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Number Of Shares owned By Affiliated Companies.

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Number of shares to be issued for One stock Acquisition Right.

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Percentage Of Common Stock outstanding owned By Affiliated Companies.

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Percentage of Option vest on grant date.

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Provision for Retained Earnings Appropriated for Legal Reserve.

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Share Based Compensation Expense After Tax.

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Shareholder equity available for dividend under the act.

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Represents the expense recognized during the period arising from share-based compensation arrangements (for example, shares of stock, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64
-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph g(1)

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14
-Section F

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The per share price that the individual must pay to acquire shares under the deferred compensation arrangement.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph a

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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 15
-Subparagraph 5
-Article 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
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The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph c(2)

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Total of Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity including portions attributable to both the parent and noncontrolling interests (previously referred to as minority interest), if any. The entity including portions attributable to the parent and noncontrolling interests is sometimes referred to as the economic entity. This excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 25

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 26

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A3
-Appendix A

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Komatsu Ltd. Shareholders' Equity (Details Textuals) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2011 USD ($)	Mar. 31, 2011 JPY (¥)	Mar. 31, 2010 USD ($)	Mar. 31, 2010 JPY (¥)	Mar. 31, 2009 JPY (¥)	Sep. 01, 2010	Sep. 01, 2009	Mar. 31, 2008 JPY (¥)
Komatsu Ltd Shareholders Equity (Textuals) [Abstract]
Increase in capital surplus incase of applying certain US practices	$ 1,243,241	¥ 103,189,000
Affiliated companies owned number of shares	1,104,600	1,104,600	1,094,600	1,094,600
Percentage of affiliated companies owned shares	0.11%	0.11%	0.11%	0.11%
Acts provision for Retained Earnings Appropriated for Legal Reserve	amount equal to 10% of retained earnings distributed each fiscal period shall be appropriated as a capital surplus or a legal reserve until the total amount of capital surplus and legal reserve becomes equal to 25% of the amount of common stock	amount equal to 10% of retained earnings distributed each fiscal period shall be appropriated as a capital surplus or a legal reserve until the total amount of capital surplus and legal reserve becomes equal to 25% of the amount of common stock
Total shareholder equity	11,719,036	972,680,000	1,056,843	876,799,000	848,334,000			917,365,000
Shareholder equity available for dividend under the act	3,551,060	294,738,000
Payment Of Cash Dividend	233,361	19,369,000
Number of share acquisition rights issued to employees	768	768	642	642	463
Number of shares to be issued for One stock Acquisition Right	100	100	1,000	1,000
Compensation expense recorded in selling, general and administrative under fair value method	1,651	137,000		413,000	376,000
Compensation expense after tax	976	81,000		246,000	224,000
Intrinsic values of options exercised	$ 2,398	¥ 199,000		¥ 153,000	¥ 722,000
Percentage of Option vest on grant date	100.00%	100.00%				100.00%	100.00%
Multiplying factor for Purchase Price			1.05	1.05
Deferred Compensation Arrangement with Individual, Exercise Price		¥ 1