The accompanying video posted by Sony strongly emphasizes the number 1. This is presumably a reference to the Xperia 1 V but also to the 1-inch large Sony IMX989 sensor it plans to use.
The Sony Xperia 1 V does not promise to be the first smartphone with this camera sensor. Also the Xiaomi 13 Pro, Oppo Find X6 Pro and Vivo X90 Pro feature this large sensor. That all these phones bear the name "Pro" is no coincidence. Because of its size, the IMX989 image sensor can shoot professional-looking photos.
1-inch large camera sensor
This is not Sony's first use of a 1-inch large camera sensor. The Xperia Pro-I has that honor. That phone had a recommended retail price of 1,800 euros at release. The Xperia 1 V promises to come out for less, although we're still counting on a hefty starting price.
Other Xperia 1 V specifications
Other specifications of the Sony Xperia 1 V are a periscope camera with variable optical zoom, a Snapdragon 8 Gen 2 processor with 12+256GB and 16+512GB of RAM+storage memory. The screen will presumably remain at a 4K resolution and smooth 120Hz display. The battery will also likely remain 5000mAh in size with 30W fast charging. Sony's press event starts May 6 at 13:00 Japanese Time and 06:00 Central European Time and can be followed online at Sony's YouTube channel.