This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
The sonatas of Emanuel Bach (C. P. E. Bach) are exemplary works that showcase his unique musical style. This sonata reflects his innovative approach during the transitional period to Classical music. The first movement is characterized by its lively and energetic motion, featuring a compelling rhythm and melody that captivate the audience. The following second movement possesses deep emotion and an introspective atmosphere, demonstrating Bachʼs richness in emotional expression. The final third movement offers a light and lively finale, beautifully concluding the overall structure. This sonata is a work that combines Bachʼs emotional expressiveness with technical prowess, embodying the diversity and depth of his music.
The second movement, ʼLargo e mesto,ʼ is longer than many of the middle movements Bach composed at the time and possesses an operatic character. Its dramatic harmonic changes are punctuated by ʼorchestralʼ chords. At first glance, this movement seems to end with a cadence in the main key (G minor), but this cadence is immediately blurred by a three-bar transition, seeking resolution in the key of the next movement."
For an overview of Wq. 65 as a whole, see Sonata Collection Wq. 65 .