SCHEDULE 13D 0002061808 XXXXXXXX LIVE Class A ordinary shares, par value US$0.000125 per share 03/12/2025 false 0001835724 98955N207 Zhihu Inc.

18 Xueqing Road Haidian District Beijing F4 100083

Tsang Suk Han 85227602518 1/F, 208 Central Des Voeux No. 308 Des Voeux Road Central Hong Kong K3 00000 0002061808 N Plus Channel Limited SC N D8 12500709.00 0.00 12500709.00 0.00 12500709.00 N 5.0 CO Shareholding includes (i) 11,934,909 Class A ordinary shares in the form of 3,978,303 ADSs and (ii) 565,800 Class A ordinary shares held by Plus Channel Limited. The percentage of the class of securities is calculated by dividing the number of shares beneficially owned by the reporting person by a total of 249,124,676 issued and outstanding Class A ordinary shares of the issuer as of February 28, 2025. Y Kastle Limited SC N K3 12500709.00 0.00 12500709.00 0.00 12500709.00 N 5.0 HC Shareholding includes (i) 11,934,909 Class A ordinary shares in the form of 3,978,303 ADSs and (ii) 565,800 Class A ordinary shares held by Plus Channel Limited. The percentage of the class of securities is calculated by dividing the number of shares beneficially owned by Plus Channel Limited by a total of 249,124,676 issued and outstanding Class A ordinary shares of the issuer as of February 28, 2025. Class A ordinary shares, par value US$0.000125 per share Zhihu Inc. 18 Xueqing Road Haidian District Beijing F4 100083 Plus Channel Limited Kastle Limited 1/F, 308 Central Des Voeux, No. 308 Des Voeux Road Central, Hong Kong Plus Channel Limited - A holding company for repurchasing the issuer's securities Kastle Limited - Sole shareholder and director of Plus Channel Limited No No Plus Channel Limited - British Virgin Islands Kastle Limited - Hong Kong Since 2022, the Issuer established certain share repurchase programs, pursuant to which the Issuer authorizes and instructs the filing persons to conduct share repurchases on the New York Stock Exchange and the Stock Exchange of Hong Kong Limited. The funds were provided by the Issuer from its working capital. The information set forth in Item 3 is hereby incorporated by reference in its entirety. The reporting persons hold the Class A ordinary shares they beneficially owned on trust under the Issuer's share incentive plan adopted in 2022. The responses of each Reporting Person to Rows (7) through (13) of the cover pages of this Schedule 13D are hereby incorporated by reference in this Item 5. The reporting persons in aggregate own 12500709 Class A ordinary shares of the issuer, including (i) 11,934,909 Class A ordinary shares in the form of 3,978,303 ADSs and (ii) 565,800 Class A ordinary shares held by Plus Channel Limited. Plus Channel Limited is wholly-owned by Kastle Limited. The percentage of the class of securities is calculated by dividing the number of shares beneficially owned by the reporting person by a total of 249,124,676 issued and outstanding Class A ordinary shares of the issuer as of February 28, 2025. 12500709; see the response to Item 5(a). Plus Channel Limited had been repurchasing the issuer's shares during the past 60 days, with a repurchase of 90,465 Class A ordinary shares in the form of 30,155 ADSs on March 12, 2025 that made the shareholding of the reporting persons cross the five percent threshold. Except as disclosed in this Schedule 13D, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Class A ordinary shares beneficially owned by the reporting persons. Not applicable. The information set forth in Items 3, 4 and 5 is hereby incorporated by reference in its entirety. To the best knowledge of the reporting persons, except as provided herein, there are no other contracts, arrangements, understandings or relationships (legal or otherwise) between the reporting persons and between any of the reporting persons and any other person with respect to any securities of the Issuer, joint ventures, loan or option arrangements, puts or calls, guarantees of profits, divisions of profits or loss, or the giving or withholding of proxies, or a pledge or contingency, the occurrence of which would give another person voting power over the securities of the issuer. Exhibit A - Joint Filing Agreement Plus Channel Limited /s/ TSANG SUK HAN 03/19/2025 Kastle Limited /s/ TSANG SUK HAN 03/19/2025