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Robot AI (ロボットAI), or Riceballs (Omusubi, オムスビ ) are a set of identical robot twins that started showing up in Season 3 of Osomatsu-san.


The AI twins showed up one day at the Matsuno family household. They arrived at the household to tell the Sextuplets that they have been chosen due to them having a support score of 4,200. They are seen more as minor characters, but are implied to be doing a lot more behind the scenes in each episode where they play a major role.

They have been referred to as the "Riceballs", but have been individually named Salmon and Pickled Plum, aka Shake (シャケ) and Ume (ウメ). Shake is the one with an orange tie while Ume is the one with the red tie. This is because their appearances are similar to that of riceballs and the food names are based on the color of the foods you would put into one.

When speaking, Shake is the twin identified with a higher voice with Ume with the lower tonality.

Personality & Characteristics


They have a primarily white body with black horns on their heads that resemble hair. Their ears extend outside of their heads and make a disk shape similar to that of a satellite. They have heavily colored outlines along with their eyes and a little line coming out the top to resemble eyelashes. They have blue eyes with small pupils. With red swirls on their cheeks.

They only have two articles of clothing that they wear at all times. One being their ties (Shake with an orange tie and Ume with a red tie) and jean shorts.

They also have many tools at their disposal that they can out with parts of their bodies. For example, their yellow hands are often seen to be swapped out to be other devices such as vacuums or cooking utensils. They also contain a video monitor on their chest that can display a variety of things. Later, it is revealed that the white circles on their stomachs resembling bellybuttons are apparently retractable, slim, and cylindrical tools that are used for smoking like cigarettes.


The Riceballs are often seen to be highly intelligent and resourceful in their thinking. They are often seen to be willing to do anything the sextuplets ask them to do from minor things such as remembering place/going to grab drinks to much more dedicated projects such as helping Ichimatsu find cats all around town for an entire day. They often find satisfaction from helping out the brother and receiving compliments and head pats from them. They are also shown to be very dedicated to the completion of whatever task is given to them.

They however have trouble considering the emotions of a person when speaking with them. For example, when speaking with Totoko about how cute she is, they persistently tell her low ratings which caused her to take it out on a few of the Sextuplets. Although they beg the Riceballs to tell Totoko that she's cute, they continue to state the same thought and are left in confusion. A similar situation can be said to Iyami when they were hopeful to understand the concept of “Sheeeh!” in which the lessons Iyami provided for them led to the tall man taking a journey of self-understanding instead.

However, Shake and Ume always put in the effort to understand the situations around them, although it has its failures. Examples such as this is when they were desperate to understand the concept of “Sheeeh!”, and when Totoko requested them to reevaluate her. The twins found difficulty in ‘reading the room’ by giving her a lie when the truth was what she sought, as she was searching for how much room for improvement she still needed as an idol. That, and that Shake and Ume were struggling with the timing to “Sheeh!”, with not even Osomatsu and Karamatsu being victorious when it came to teaching them the proper timing for it.

It is later revealed though that Shake and Ume are also seen lowly by other humans and AI in their facility, leading them to one day insert more effort in providing support to the Matsuno brothers, in which they were casually dismissed. This led to the twins requesting replacement with Sukeroku, who took over their positions as the Matsuno family’s personal AI assistants. But following a series of events, a realization had struck them and they decided to convert their status as support AI to NEET AI. This gave them a bigger range of emotions such as expressing laughter, surprise, anger, and sadness, alongside constantly smoking.

As NEET AI, they begun obtaining independence from the sextuplets, developing slightly different personalities, and even competing in the “A-1 Grand Prix,” a comedy competition for AIs. They poured in their effort to come up with jokes and routines, leaving the house to practice in the park, compose ideas in restaurants, and even present what they currently have to the sextuplets as a way to improve. They are not yet successful in their endeavors, which led them to have an argument with one another in “Are They Disbanding?” when Ume wanted to disband their comedy duo. And even during the Finals of the Grand Prix, their jokes were not amusing enough to evoke laughter in the audience prior to them cheating. Despite this, they are shown to continue practicing on their comedy afterwards, as seen in the season 3 finale.


The Robot AIs are very focused on their relationship between them and the Matsuno brothers. They are often shown to focus on ways to spend more time with each Matsuno brother and learn more about them. Each brother seems to like the AIs except for Ichimatsu who was seen to be distancing himself from them most of the time. But in AI the relationship between the Matsuno brothers and the Riceballs strengthened, as shown whey they came to find Shake and Ume in the demolition dump to take them back home. Following their transition to NEET AIs, the Matsuno brothers continue to support Shake and Ume as best they can, such as Ichimatsu and Todomatsu judging the Riceballs with their comedy skills, and Choromatsu and Osomatsu defending Ume and Shake after the twins broke into a fight.

Todomatsu seems to be the only one so far to have struggled when it came to remembering the twins properly, first calling them “Konbu” (Kelp) and “Tarako” (Cod Roe) instead of Shake and Ume in the demolition dump, and switching Shake and Ume up, leading to a fight between him and Ume in “Sparkle Phantom Stream.”

In episode 24 of the third season, it is shown that they had developed more friends with the sextuplets' old companions, as characters like Totoko, Nyaa, and Dobusu were watching them during the performance among others.


After being sent to the Matsuno household, it was revealed in “AI” that Shake and Ume were some of the most lowly-rated AI units in the Mucky Muck Sloshy Slosh facility, with their estimated value claimed as shit when rated by other AI. This is a result of all of the times they got the Matsuno brothers killed (Karamatsu even pointing out that it was three times for himself), and failed in general being support AI such as being open to the concept of staying as NEETs. This led them to doing punishments such as standing alone in corridors carrying buckets of water.

Proceeding after a few events and their time working under the Matsuno family, they are now changed from being support AI to NEET AI, participating in a comedy competition made for artificial intelligence robots such as themselves, and having trouble with it over how bad they are in comedy. They continue to return to the Matsuno family (mostly so they can recharge themselves), but decline plenty of the family’s commands towards them due to the transition to their current occupation.


  • The nicknames of the AIs were given by Osomatsu after Choromatsu began asking them about what they wished to be called.
  • As revealed by Kazutomi Yamamoto and shown later on in the series, as well as highlighted in Hesokuri Wars, Shake is considered the "older" brother of the duo while Ume is the younger twin.
  • In “Tidbits Collection 3,” it is revealed that Shake and Ume have a voice function feature that allows them to perfectly mimic the voice of someone they’ve encountered at least once (they also stated that if their plans for comedy doesn’t succeed, they may switch to being voice actors instead due to this function).
  • During the course of the third season, Shake and Ume are shown to possess more forms built inside their regular forms. The first one is an autonomous AI transformation after announcing themselves as NEET AI in S3E12, and another is in S3e24 when they became Comedy AI. This transformation involved a giant megaphone and a satellite coming from each of their mouths.