NOTE 5. STOCK-BASED COMPENSATION: Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award (Details) - $ / shares	12 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Details
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number, Beginning Balance	29,000	30,500
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Beginning Balance	$ 69.52	$ 68.28
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross	6,500	6,500
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 50.35	$ 74.22
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period	(1,000)	(5,000)
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 57.46	$ 61.36
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period	0	3,000
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$ 0	$ 80.75
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period	0	(3,000)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number, Ending Balance	34,500	29,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance	$ 66.26	$ 69.52
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number	32,000	24,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 63.60	$ 64.32
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 9.06	$ 13.04

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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