CERO Z explained: Japan's 18+ game rating and how it compares with PEGI 18 and AO

CERO Z is the highest age rating for console games in Japan. It marks a game as for ages 18 and over only. It is issued by CERO, the Computer Entertainment Rating Organization, and it is the one CERO rating that comes with a restriction on sale.

It is also widely misread outside Japan. Z is not the Japanese version of the ESRB’s AO rating, and it is not a rating for adult games. A Z-rated game is usually a violent one, and it is sold on every major console.

This page explains what Z means, how it differs from D, where it came from, whether it has legal force, and how it sits beside PEGI 18 and AO.

Key points

• Z means ages 18 and over only. It is CERO’s top rating.
• It dates from 1 March 2006. That is when the current system took effect.
• Z is the restricted rating. The four below it are advisory.
• CERO’s ratings have no legal force of their own. Industry rules and some local ordinances do the enforcing.
• Z games are sold on consoles. That is the main difference from AO.
• Z is not an eroge rating. Adult PC games go to other review bodies.
• A game can be refused a rating. Expression above CERO’s limits gets no mark at all.
• Some games ship in two editions. A D version and a Z version.

What CERO Z means

CERO has five age marks. Each is a letter, printed on the lower left of a game’s front cover and repeated as a coloured band on the spine.

The colours are given on CERO’s own page about the system, which also dates the current marks to a revision of 1 March 2006.

The word “only” in the Z mark is the difference. Publishers that explain the system to customers, such as Square Enix, give the four lower marks as “for ages 12 and over” and so on. For Z the wording is “for ages 18 and over only”, with a second sentence: it is a classification premised on not selling or distributing the game to people under 18.

CERO adds content icons on the back of the box to show what a rating was based on. There are nine: romance, sexual content, violence, horror, drinking and smoking, gambling, crime, drugs, and language.

CERO D and CERO Z: one year apart

D is for 17 and over and Z is for 18 and over. A one-year gap looks trivial. In practice the two ratings behave differently.

The retailer Nojima’s guide to CERO describes the content difference in those terms: the ages are a year apart, and Z titles may contain more extreme violence.

That gap is why some games exist twice. Alex Aniel’s account of the system, published in May 2024, records that Capcom released both a D edition and a Z edition of each major Resident Evil game in Japan between 2017 and 2022. The Z edition kept more of the gore and the D edition reduced or removed it. The 2023 remake of Resident Evil 4 was released with a Z rating only.

Where the Z rating came from

Before 2006 CERO had four ratings, and all four were advisory. The highest was “18 and over”.

The change began with one game. On 30 May 2005 the child welfare council of Kanagawa Prefecture designated Grand Theft Auto III a harmful publication under the prefecture’s youth protection ordinance. The designation was gazetted on 7 June 2005 and banned sale of the game to under-18s in the prefecture. Capcom had published it in Japan in 2003 with CERO’s 18-and-over rating. GAME Watch’s retrospective calls it the first time authorities restricted the sale of a game over violence.

The industry answered in two steps.

1. July 2005. The trade body CESA began asking retailers to stop selling 18-and-over titles to minors voluntarily.
2. 17 February 2006. CESA announced a revised system, reported the same day by GAME Watch. It added a 17-and-over category and renamed the top category “18 and over only”. For that category CESA would itself require the ban on sales to minors, where before it had left the decision to shops.

Reviews under the new system began on 1 March 2006. The first products with the new marks were expected around May, and the sales ban was expected to apply from June. Games already rated 18-and-over were to be reviewed again and were not moved to Z automatically.

Is CERO Z legally binding?

Not by itself. CERO is a non-profit organisation and its marks are not law. Nojima’s guide describes the rating marks as a guide to buying.

Enforcement comes from two other places.

• Industry self-regulation. CESA and retailers apply the rule that Z games are not sold to under-18s.
• Local ordinances. Prefectures can write CERO’s ratings into their youth protection rules. Nojima gives two examples: Kanagawa’s ordinance asks that Z games not be sold to minors, and Shizuoka designates them as harmful publications, which bans sale and rental to minors.

A Z rating also has a commercial cost. Aniel writes that it can mean little in-store promotion or a shop declining to stock the game. Nojima itself stopped selling Z-rated games in its stores on 1 April 2023.

What CERO looks at

CERO’s page lists the expressions it reviews under four headings. The sexual heading includes kissing, embracing, exposed underwear, sexual acts, nudity, suggestive expression, and swimsuits and costumes. The violence heading includes blood, dismemberment, corpses, killing and wounding, and horror. The other two cover antisocial acts, such as crime and drugs, and language and ideology.

Two rules follow from that list.

Every item has a ceiling. CERO states that each expression has an upper limit, that expression above the limit is a “banned expression”, and that software containing one is given no rating. Z is therefore not an “anything goes” rating. It is the top of a scale that stops.

Raters come from outside the industry. CERO says its raters are members of the public aged from their twenties to their sixties, in a range of occupations, trained by CERO and bound by confidentiality. People connected with the games industry are not taken on.

A game with no rating cannot be released on the consoles that require one. In October 2022 the Japanese release of The Callisto Protocol was cancelled after it failed CERO’s review, as Automaton reported. The developer said the game could not pass in its current state and that changing it would not give players the experience they expected.

CERO Z compared with PEGI 18 and AO

The three ratings share an age and little else.

The row about consoles is the important one. Nintendo, Sony and Microsoft do not allow AO-rated games on their systems, which is why almost no game carries that rating. We cover the reasons in the AO rating explained. Z has no such barrier, and Z-rated games are released on PlayStation, Xbox and Nintendo hardware in Japan.

The nearest equivalent to Z is PEGI 18, the ordinary top rating in Europe. The Resident Evil games that carry a Z in Japan, for example, are rated M (Mature 17+) by the ESRB and not AO.

Japan’s digital stores add one twist. Automaton reported that from 9 March 2022 the Japanese PlayStation Store began accepting ratings from IARC, the international system, for digital-only games. It reported that Sony still asks for a CERO rating where IARC gives a game 18+.

Why Z is not an adult game rating

People searching for Z often expect it to mark eroge. It does not.

Japan reviews games through separate bodies. Wikipedia’s survey of video game content rating systems sets out the split.

CERO’s own scope does list personal computers and smartphones beside the consoles. In practice the adult PC game trade uses the other two bodies, and their 18+ mark is the one found on eroge.

So the two kinds of “18” mean different things. A Z on a console box says the game is too violent or too strong for minors within CERO’s limits. An 18+ mark on a PC game says it is an adult title reviewed under a separate code. For that side of the industry, see mosaic censorship meaning, adult game terms explained and bishoujo game meaning.

What this means for developers

A studio making an adult game is unlikely to meet CERO directly. Three points are still worth knowing.

1. A console release in Japan needs a rating. The digital stores accept IARC for many games, and the reporting above says the strictest content still goes to CERO.
2. CERO has ceilings. A game above them is refused a rating, with no higher mark to move to.
3. Adult PC games take another route. Their review bodies, stores and payment rules are separate, and we cover the stores in DLsite vs Steam.

For how ratings fit the wider picture, see what are adult games.

What is still unknown

• The exact ceilings. CERO points to a table in its ethics code for banned expressions. We did not read that table and do not quote it.
• How many prefectures write Z into ordinances. Nojima names two as examples and gives no total.
• Whether Sony’s 18+ rule for the PlayStation Store still stands. The reports we found date from 2022.
• How often Z games are refused shelf space. Nojima’s decision is documented. We found no figures for other chains.

How this page was put together

The marks, colours, review items and rater rules come from CERO’s own page, read in Japanese on 12 October 2026. The wording of the Z category is taken from Square Enix’s customer page, and the translation is ours. The history comes from GAME Watch’s reports of 2006 and 2024. The retail details come from Nojima’s guide and from Alex Aniel’s article, which is one writer’s account.

The studio has not submitted a game to CERO, and nothing here is a first-hand account of its review.

This page was written on 12 October 2026. To report an error, see the corrections standard.