Katen (a Touhou LW original) refers to the sky on a bright, sunny day. This is an apt temperament for Youmu, the half-human half-phantom of the world of eternal summer. To make sushi, you need rice (strong against Earth Phase), fish and vinegar (strong against Wood Phase), and salt (strong against Water Phase). However, it really is best eaten raw... (Weak against Fire Phase.)

The ability of Youmu Konpaku from the world of eternal summer (a Touhou LW original). This ability isn't any different from the Youmu of our world's ability. However, in this world, she has become more of a chef than a swordswoman. To the surprise of no one, Yuyuko's demands were completely out there. Supposedly, Youmu and Yuyuko came down from the Netherworld to investigate the unusual temperament, but Yuyuko herself said they were on an "all-you-can-eat tour of Gensokyo." Then again, Yukari is accompanying them, so everything should be fine. Probably. Yuyuko also ordered Youmu to perfect her culinary skills... which left Youmu with even more questions. Caught up in the cheery atmosphere of the eternal summer world, the Saigyou Akayashi transformed into a palm tree, and the other cherry tree phantoms transformed into fruit trees. This turned Hakugyokurou's garden into an orchard, which Youmu happily decided to take care of as part of her duties. The fruit Youmu picked from this new orchard was fairly well-received by Yuyuko. Youmu thought the tree phantoms had it pretty good, considering they could freely transform into tree varieties that were guaranteed to produce high-quality fruit. However, she couldn't spend much time out in the garden and orchard because, for some reason, she had to perfect her cooking skills. She decided to start this journey by experimenting with fruit sushi. Youmu thought it tasted good, but Yuyuko hated it, so she headed down to Gensokyo to try making sushi using ingredients from the sea. "This one's no good. You have to use fresher ingredients. This one wasn't cut properly. This one needed more seasoning... I had to eat them all because they weren't good enough to serve to other people." Despite this harsh feedback, Yuyuko seemed to enjoy "taste-testing" Youmu's dishes... For Youmu to cook a dish capable of satisfying her mistress, she would need to find the perfect recipe and master the skills and techniques required to make it a reality. Her cooking skills had never been put to the test like this before. She was like a swordswoman who had trained to a high level in the dojo but had never seen actual combat. She figured that what she needed most of all was speed! Sushi is raw food, seafood, and food for the soul, but it is also fast food! There have been many innovations in sushi preparation and serving techniques over the years to make it more efficient at filling the bellies of hard-working city folk. Youmu planned to use these techniques to prepare sushi so fast that Yuyuko would always have her mouth full, preventing her from saying anything bad. If she kept at it, there would surely come a day when her mistress was too stuffed to eat any more... Youmu had started to think that anything could be used for sushi as long as you knew the right way to cut it. She tried vegetables, fruits, wood, dirt, rocks, and chunks of the Izanagi Plate... and Yuyuko happily ate them all up. She thought she was really on to something. "There isn't much that I can't turn into sushi!" Please, someone stop her before it's too late.