Exhibit 5.1

*licensed in CA, FL and NY

**licensed in FL and NY

*** licensed in CA

****licensed in CA, DC, MO and NY

***** licensed in MO

******licensed in NY and NJ

*******licensed in NY and NJ

********licensed in CA and HI (inactive in HI)

July 13, 2026

Advasa Holdings, Inc.

1-2-7 Moto-Akasaka

Minato-ku, Tokyo, 107-0051 Japan

Ladies and Gentlemen:

We have acted as counsel for Advasa Holdings, Inc., a Delaware corporation (the “Company”) in connection with the preparation and filing of a certain Registration Statement on Form S-1 (as amended, the “Registration Statement”) under the Securities Act of 1933, as amended (the “Securities Act”). The Registration Statement relates to the resale by the selling stockholders (the “Selling Stockholders”) set forth in the Registration Statement of 94,075,607 shares of Common Stock (the “Shares”). The Shares are proposed to be sold by the Selling Stockholders from time to time in accordance with the Plan of Distribution contained in the Prospectus.

As counsel to the Company, we have examined the originals or copies of such documents, corporate records and other instruments and undertaken such further inquiry as we have deemed necessary or appropriate for purposes of this opinion, including, but not limited to, the Registration Statement, corporate resolutions authorizing the issuance of the Shares and the Certificate of Incorporation and Bylaws of the Company, including amendments thereto. In such examination, we have assumed the following: (a) the authenticity of original documents and the genuineness of all signatures; (b) the legal capacity of all natural persons, the accuracy and completeness of all documents submitted to us; (c) the conformity to the originals of all documents submitted to us as copies; (d) the genuineness of all signatures contained in the records, documents, instruments and certificates we have reviewed; and (e) the truth, accuracy and completeness of the information, representations and warranties contained in the records, documents, instruments and certificates we have reviewed. This opinion letter is given, and all statements herein are made, in the context of the foregoing.

1700 PALM BEACH LAKES BLVD., SUITE 820 ● WEST PALM BEACH, FLORIDA ● 33401 ● PHONE: 561-514-0936

Based on and subject to the foregoing, we are of the opinion that upon the effectiveness of the Registration Statement the Shares are duly authorized by all necessary corporate action of the Company and are validly issued, fully paid and nonassessable.

Notwithstanding anything in this letter which might be construed to the contrary, our opinion expressed herein is limited to the General Corporation Law of the State of Delaware and the Federal laws of the United States of America. We express no opinion with respect to the applicability to, or the effect on, the subject transactions of the laws of any other jurisdiction or as to any matters of municipal law or the laws of any local agencies. The opinion expressed herein is based upon the General Corporation Law of the State of Delaware and Federal laws of the United States of America in effect on the date hereof and as of the effective date of the Registration Statement, and we assume no obligation to revise or supplement this opinion after the effective date of the Registration Statement should such law be changed by legislative action, judicial decision, or otherwise. Except as expressly set forth in our opinion above: (i) we express no opinion as to whether the laws of any other jurisdiction are applicable to the subject matter hereof and (ii) we express no opinion as to compliance with any other federal or state law, rule or regulation relating to securities, or to the sale or issuance thereof.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to our firm appearing under the caption “Legal Matters” in the prospectus that forms a part of the Registration Statement. In giving this consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act, or the rules and regulations promulgated thereunder.

Sincerely yours,