Riku Ichikawa (市川 りく, Ichikawa Riku) is a Japanese AV (adult video) actress from Okinawa Prefecture who is affiliated with LiStar PRO. Her body measurements are 82-58-89 cm (D cup) and she is 1.62 m tall.

In 2018, she joined Stardom★Idols, an idol unit produced by Tamu Nakano, debuting in December of the same year. In January 2019, she became a trainee for the professional wrestling organization Stardom, but left in April.

In January 2021, she made her entertainment industry debut as Ushio Shiina (しいな うしお, Shīna Ushio), a 10th generation member of Sanspo Idol Reporter (SIR). However, on January 8, 2022, she was dismissed from SIR and her agency (Idol Dream) due to a serious breach of contract (the details of the breach were not disclosed). Her birth date as Shiina Ushio was January 24, 1999.

In July 2022, she made her AV debut as an exclusive Kawaii* actress under the stage name Riku Ichikawa (市川 りく). With the work released in April 2023, she will left the exclusive contract and became a project-only actress