[LETTERHEAD OF PATTERSON BELKNAP WEBB & TYLER LLP]

December 9, 2005

Citibank, N.A. - ADR Department
388 Greenwich Street
New York, New York 10013

Ladies and Gentlemen:

            We refer to the Registration Statement on Form F-6 (the
"Registration Statement") to be filed with the Securities and Exchange
Commission (the "SEC") by the legal entity created by the Deposit Agreement (as
hereinafter defined) for the purpose of registering under the U.S. Securities
Act of 1933, as amended (the "Securities Act"), 100,000,000 American Depositary
Shares (the "ADSs") to be evidenced by American Depositary Receipts (the "ADRs")
to be issued under the Deposit Agreement, dated October 1, 1982, by and among
Citibank, N.A., as Depositary, Mitsui & Co., Ltd., a company organized under the
laws of Japan (the "Company"), and the Holders from time to time of ADRs and
European Depositary Receipts (the "EDRs") issued thereunder (a copy of which is
being filed as exhibit (a)(ii) to the Registration Statement), as proposed to be
amended by Amendment No. 1 to the Deposit Agreement (the Deposit Agreement as so
amended, the "Deposit Agreement"), by and among the Company, the Depositary, and
the Holders of ADRs and EDRs (a draft copy of which is being filed as exhibit
(a)(i) to the Registration Statement). Each ADS will represent, subject to the
terms and conditions of the Deposit Agreement and the applicable ADR
representing such ADS, twenty (20) shares of common stock of the Company (the
"Shares").

            Nothing contained herein or in any document referred to herein is
intended by this firm to be used, and the addressees hereof cannot use anything
contained herein or in any document referred to herein, as "tax advice" (within
the meaning given to such term by the U.S. Internal Revenue Service ("IRS") in
IRS Circular 230 and any related interpretative advice issued by the IRS in
respect of IRS Circular 230 prior to the date hereof, and hereinafter used
within such meaning and interpretative advice). Without admitting that anything
contained herein or in any document referred to herein constitutes "tax advice"
for any purpose, notice is hereby given that, to the extent anything contained
herein or in any document referred to herein constitutes, or is or may be
interpreted by any court, by the IRS or by any other administrative body to
constitute, "tax advice," such "tax advice" is not intended or written to be
used, and cannot be used, for the purpose of (i) avoiding penalties under the
U.S. Internal Revenue Code, or (ii) promoting, marketing or recommending to any
party any transaction or matter addressed herein.

            Assuming that, at the time of their issuance, the Registration
Statement will have been declared effective by the SEC, the Deposit Agreement
will have been duly executed and delivered, and the Shares will have been
legally issued, we are of the opinion that the ADSs, when issued in accordance
with the terms of the Deposit Agreement and the Registration Statement, will be
legally issued and will entitle the "record holders" (as defined in the Deposit
Agreement) of ADRs to the rights specified in the Deposit Agreement and the
applicable ADR(s).



Page 2

            This opinion is limited to the laws of the State of New York and the
Federal laws of the United States. Without admitting that we are within the
category of persons whose consent is required under Section 7 of the Securities
Act, we hereby consent to the use of this opinion as Exhibit (d) to the
Registration Statement.

                                            Very truly yours,

                                            PATTERSON, BELKNAP, WEBB & TYLER LLP


                                            By: /s/ Herman H. Raspe
                                                --------------------------------
                                                A Member of the Firm