Form: 10-K

Annual report [Section 13 and 15(d), not S-K Item 405]

March 6, 2026

EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of Black Spade Acquisition III Co (the “Company”) on Form 10-K for the fiscal year ended December 31, 2025, as filed with the Securities and Exchange Commission (the “Report”), I, Dennis Tam, Executive Chairman of the Board and Co-Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that, to the best of my knowledge:

1.

The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2.

The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: March 6, 2026

/s/ Dennis Tam

Dennis Tam

Executive Chairman of the Board and Co-Chief Executive Officer

(Principal Executive Officer)