Ginga tetsudō de i kō! ! Shūchakueki

Sole female indicates that a gallery features exactly one female character throughout the entire work. This tag is important for readers who prefer focused, intimate scenarios rather than group dynamics or harems. It doesn't imply anything about the number of male partners — a sole female gallery can feature one male partner (sole male) or multiple. The tag helps distinguish between different relationship dynamics and is commonly paired with tags like 'sole male' for one-on-one scenarios or 'multiple male' for gangbang-type content. In terms of narrative structure, sole female works often develop a single relationship or encounter in depth rather than juggling multiple characters.

Tentacles (触手, shokushu) is a genre tag covering tentacle monsters and their interactions with characters. This is a distinctive genre in hentai with roots in Japanese horror and fantasy art. The tentacles can range from realistic sea creatures to fantasy monsters. The genre often features non-consensual scenarios and is closely related to 'monster' and 'rape' tags.