SPAC Offering Forepart, De-SPAC Consummation Timeframe Description [Text Block]

We will have 24 months from the closing of this offering (or 27 months from the closing of this offering if we have executed a letter of intent, agreement in principle or definitive agreement for an initial business combination within 24 months from the closing of this offering), or until such earlier liquidation date as our board of directors may approve, to consummate an initial business combination, which we refer to herein as the completion window.

SPAC Offering Forepart, Security Holder Redemptions Subject to Limitations [Flag]

true

SPAC Offering Forepart, Adjusted Net Tangible Book Value Per Share [Table Text Block]

The following table illustrates the difference between the public offering price per unit and our net tangible book value per share, as adjusted to reflect various potential redemption levels that may occur in connection with the closing of our initial business combination, which we refer to as Adjusted NTBVPS, on a pro forma basis to give effect to this offering and the issuance of the private placement warrants, assuming no exercise of the over-allotment option and exercise of the over-allotment option in full. Adjusted NTBVPS excludes the effect of the consummation of our initial business combination or any related transactions or expenses. See the section titled “Dilution” for more information.

As of September 5, 2025

25% of Maximum

50% of Maximum

75% of Maximum

Maximum

Offering

Redemption (assumes

Price of

3,750,000 or 4,312,500

7,500,000 or 8,625,000

11,250,000 or 12,937,000

15,000,000 or 17,250,000

$10.00

public shares redeemed)

Difference

between

Adjusted

NTBVPS

and

Adjusted

Offering

Adjusted

Offering

Adjusted

Offering

Adjusted

Offering

NTBVS

NTBVPS

Price

NTBVPS

Price

NTBVPS

Price

NTBVPS

Price

Assuming Full Exercise of Over-Allotment Option

$

7.25

$

6.71

$

3.29

$

5.84

$

4.16

$

4.22

$

5.78

$

0.19

$

9.81

Assuming No Exercise of Over-Allotment Option

$

7.25

$

6.70

$

3.30

$

5.83

$

4.17

$

4.22

$

5.78

$

0.18

$

9.82

SPAC Offering Prospectus Summary [Line Items]

SPAC Will Solicit Shareholder Approval for De-SPAC Transaction [Flag]

false

SPAC, Trust or Escrow Account, Gross Offering Proceeds Placed, Amount

$ 150,000,000

SPAC, Securities Offered, Material Terms [Text Block]

15,000,000 units (or 17,250,000 units if the underwriters’ over-allotment option is exercised in full), at $10.00 per unit, each unit consisting of:

·one Class A ordinary share; and

·one-third of one redeemable warrant.

De-SPAC Consummation Timeframe, Duration

24 months

SPAC Prospectus Summary, Sponsor Compensation [Table Text Block]

The following table sets forth the payments to be received by our sponsor and its affiliates from us prior to or in connection with the completion of our initial business combination and the securities issued and to be issued by us to our sponsor or its affiliates, assuming the underwriters’ over-allotment option is not exercised:

Entity/Individual	Amount of Compensation to be Received or Securities Issued or to be Issued	Consideration Paid or to be Paid
Black Spade Sponsor LLC III	5,000,000⁽¹⁾ Class B ordinary shares (which include anti-dilution adjustments as described in “— Founder shares conversion and anti-dilution rights”)⁽²⁾	$25,000 (approximately $0.004 per share)
Black Spade Sponsor LLC III	6,550,000 private placement warrants to be purchased simultaneously with the closing of this offering	$3,275,000 ($0.50 per private placement warrant)
Black Spade Sponsor LLC III	$20,000 per month, commencing on the first date on which our securities are listed on the Nasdaq	An aggregate of $20,000 per month for up to 24 months for office space, and administrative and support services.
Black Spade Sponsor LLC III	Repayment in cash	Up to $250,000 of loans made to us to cover offering related and organizational expenses
Black Spade Sponsor LLC III or its respective affiliates	Repayment in cash or in private placement warrants at a conversion price of $0.50 per warrant	Working capital loans to finance transaction costs in connection with an initial business combination. Up to $3,500,000 of such loans may be converted at the option of the lender into private placement warrants at a conversion price of $0.50 per warrant
Black Spade Sponsor LLC III, officers, directors, or their respective affiliates	Payment of consulting, success or finder fees to our officers, independent directors, or their respective affiliates in connection with the consummation of our initial business combination	Any services in order to effectuate the completion of our initial business, which, if made prior to the completion of our initial business combination, will be paid from funds held outside the trust account

SPAC Offering Dilution [Line Items]

SPAC, Material Potential Source of Future Dilution of Shares not Tendered [Text Block]

The difference between the public offering price per Class A ordinary share and Adjusted NTBVPS, on a pro forma basis to give effect to this offering and the issuance of the private placement warrants, assuming no exercise of the over-allotment option and exercise of the over-allotment option in full, constitutes the dilution to investors in this offering. Adjusted NTBVPS is determined by dividing our net tangible book value, which is our total tangible assets less total liabilities (including the value of Class A ordinary shares which may be redeemed for cash), as adjusted to reflect various potential redemption levels that may occur in connection with the closing of our initial business combination, by the number of Class A ordinary shares issued and outstanding.

Adjusted NTBVPS excludes the effect of the consummation of our initial business combination or any related transactions or expenses. The calculation of Adjusted NTBVPS (A) assumes that (i) no ordinary shares are issued to shareholders of a potential business combination target as consideration or issuable by a post-business combination company, for instance under an equity or employee share purchase plan, (ii) no ordinary shares and convertible equity or debt securities are issued in connection with additional financing that we may seek in connection with an initial business combination, and (iii) no working capital loans are converted into private placement warrants, as further described in this prospectus, and (B) assumes the issuance of 15,000,000 Class A ordinary shares included in the units sold in this offering (or 17,250,000 Class A ordinary shares included in the units sold in this offering if the underwriters’ over-allotment option is exercised in full) and 5,750,000 founder shares (up to 750,000 of which are assumed to be forfeited in the scenario in which the underwriters’ over-allotment option is not exercised in full).

Generally, the dilution that our public shareholders will experience increases the more public shares are redeemed. The issuance of additional ordinary or preference shares may also significantly dilute the equity interest of investors in this offering, which dilution would even further increase if the anti-dilution provisions in the Class B ordinary shares resulted in the issuance of Class A ordinary shares on a greater than one-to-one basis upon conversion of the Class B ordinary shares. Any ordinary shares and convertible equity or debt securities issued in connection with additional financing that we may seek in connection with an initial business combination, or issued upon the exercise of warrants upon the conversion of working capital loans converted into private placement warrants, as further described in this prospectus, would also significantly dilute the equity interests of investors in this offering.

In addition, because of the anti-dilution protection in the founder shares, any equity or equity-linked securities issued in connection with our initial business combination would be disproportionately dilutive to our Class A ordinary shares. In addition, because we intend to target businesses with enterprise values that are greater than we could acquire with the net proceeds of this offering and the sale of the private placement warrants, if the cash portion of the purchase price exceeds the amount available from the trust account, net of amounts needed to satisfy any redemption by public shareholders, we may be required to seek additional financing to complete such proposed initial business combination. We cannot assure you that such financing will be available on acceptable terms, if at all. We also may be required to obtain additional financing in connection with the closing of our initial business combination for general corporate purposes, including for maintenance or expansion of operations of the post-transaction businesses, the payment of principal or interest due on indebtedness incurred in completing our initial business combination, or to fund the purchase of other companies. In addition, even if we do not need additional financing to complete our initial business combination, we may require such financing to fund the operations or growth of the target business. If we seek additional financing through the issuance of equity or equity-linked securities, such issuances would be disproportionately dilutive to our Class A ordinary shares. For more information on risks related to dilution also see “We may issue additional Class A ordinary shares or preference shares to complete our initial business combination or under an employee incentive plan after completion of our initial business combination. We may also issue Class A ordinary shares upon the conversion of the founder shares at a ratio greater than one-to-one at the time of our initial business combination as a result of the anti-dilution provisions contained in our amended and restated memorandum and articles of association. Any such issuances would dilute the interest of our shareholders and likely present other risks.” Our public shareholders will experience dilution even if no public shares are redeemed in connection with an initial business combination or another redemption event, for instance in connection with the implementation by our board of directors of, following a shareholder vote, an amendment to our amended and restated memorandum and articles of association (A) to modify the substance or timing of our obligation to provide holders of our Class A ordinary shares the right to have their shares redeemed or repurchased in connection with our initial business combination or to redeem 100% of our public shares if we do not complete our initial business combination within 24 months from the closing of this offering or (B) with respect to any other provision relating to the rights of holders of our Class A ordinary shares.

However, while our public shareholders will experience dilution even if none of our public shares are redeemed, the dilution they will experience will decrease the more of our public shares remain issued and outstanding following a redemption event. For instance, if we seek shareholder approval of our initial business combination and we do not conduct redemptions in connection with our initial business combination pursuant to the tender offer rules, our sponsor, directors, executive officers, or their affiliates may purchase units, public shares, warrants or equity-linked securities in privately negotiated transactions or in the open market either prior to or following the completion of our initial business combination, although they are under no obligation to do so. In the event of any such purchases of our shares prior to the completion of our initial business combination or if we enter into non-redemption agreements with certain of our shareholders, the number of Class A ordinary shares subject to redemption will be reduced by the amount of any such purchases or shares subject to non-redemption agreements, increasing the pro forma net tangible book value per share. See “Proposed Business — Our Initial Business Combination — Permitted Purchases of Our Securities.”