Used in Russia and certain other post-Soviet states, the Soviet system of education changed little since its establishment — well, it can be said that the Soviet/Russian (and other post-Soviet systems largely based on it, like Ukrainian or Kazakh ones) educational system is in constant state of reform, but in fact this reform changes only superficial details and mainly consists of piling ever more paperwork and lecture hours on a teacher, the basis of the system remains adamant. Before the Revolution Russia used a system very similar to the German one, and after a brief period of revolutionary experimentation it was largely recreated as it was (changing only the names of institutions; the pre-Revolution system was a carbon copy of the German one down to the names of schools like Gymnasium, Realschule etc.). It starts when the child is 6 years old, and the minimum compulsory amount of school is 9 years.
Srednyaya shkola (Middle school)Elementary, junior high and high do not exist in the post-Soviet system as separate schools. There is some rudimentary division between "nachalnaya" (elementary) and "srednyaya" (middle) periods of schooling, but both happen continuously in the same building called middle school. Elementary school (including a daycare unit, which exist in most post-Soviet schools, called "Школа продлённого дня" or Extended Day School) is usually given a separate floor or wing in a school building though. Another notable difference is that while in elementary school there is only one teacher who teaches her class on every subject, and each class has its own room, in middle school there are multiple teachers and the rooms are assigned to the teacher instead of class — a so-called "Room System". Formal length of elementary schooling is 4 years, but the transition is pretty gradual; disciplines like foreign language (usually English), literature, history, physics are added to the curriculum one by one each year, so the first year of junior high differs from the last year of elementary mainly in how a school day is organized. Soviet (and thus most post-Soviet) school system was largely based on a Tsarist one, which itself was largely a copy of a German system. The student body is broken into school years and each year divided into the fixed groups of ~30 students called classes, and class grouping would usually persist for the whole duration of school, bar explicit student movement or reshuffle. Every such class is given a homeroom teacher responsible for overseeing the administrative, academical and disciplinary affairs of this class, and such teachers have quite a lot of power, both official and unofficial over their students. Each year would follow the standardized and unified curricula with the centrally approved content, it was often said that in the Soviet Union you could've correctly predicted what textbook page was opened in every classroom of the whole country based only on a day of the year. In the late 80es there was some attempt to introduce a more flexible curriculum, but it didn't stick, mainly because this would require the complete reshuffle of both pedagogical and administrative structure of educational system. The grade system is supposedly five-tiered, 1 being the worst and 5 the best, but in reality it's four-tiered; the 1 grade was discontinued after the Revolution, and the equivalent to the F grade is 2. Currently, in some schools, teachers are reluctant to use 2s, too, making the system practically three-tiered. Some post-Soviet countries that kept the system as a whole ditched the grades and invented their own. As noted above, the compulsory education is 9 years, but the middle school as a whole is 11 years long. The high school's two years, commonly called "старшая школа" (senior school), aren't mandatory, but they are free, like the rest of the middle school system (state school, mind you, there's no shortage of private schools, which are paid — all teach the same standardized curricula, though, the difference is mainly in that private schools usually have better equipment, better amenities and pay better, thus attracting better teachers), and they are necessary to enroll in a university. Those who leave school after 9 years are limited to vocational (or professional) schools instead. Otherwise the high school is basically "more of the same", with the subjects explored deeper and in more detail. There is also the possibility to enter some "specialized class" which has a curriculum better suited to prepare the student to entering a university of their choice. Also, most American high school tropes don't work here, because the students are broken in relatively small groups that have limited interaction between themselves, and often have inter-class rivalry to boot.
Vocational school (srednyaya spetsialnaya/professionalnaya, or middle special/professional)There are several varieties of the vocational schools in the post-Soviet systems, but they are largely broken into the two distinct types. First one, a so-called middle professional school, and exemplified by the late-Soviet PTUs ("Профессионально-техническое училище", a Professional-Technical School) is a two-year institution that prepares a student to some blue-collar job, by teaching the basic skills in a selected field (not necessarily technical or industrial, both service schools and agricultural schools belong here, for example). These schools are also the main body of professional certification in Russia at least — there's no professional bodies that issue the vocational certificates in Russia, and to obtain a certificate one must finish such a school, if only formally by passing a graduation exam, if the skill is self-taught for example. On the other hand, such certificates are rarely, if at all, asked by the employers hiring a blue-collar worker. PTUs (previously often called Artisanal Schools) are also the closest equivalent that Russia and environs have to an Inner City School — the trope in its purest form is little known there, as there is not as much urban segregation. On the other hand, there is a distinct trend for the normal middle schools to dump their dunces and troublemakers as soon as possible (which means after the 9th year), most of whom usually end up here, as there is no entrance examination, so discipline was, and still is, a major problem for these schools, and drinking, smoking and teenage sex are common. It helps, though, that the teachers there (well, in the middle schools often too, but if is frowned upon more there) aren't afraid to discipline their pupils, and many are of the persuasion that saving a rod is spoiling the child, so these are pretty rough and tough establishments. In contrast, the second vocational school type, the middle special school, usually called "Technicum", is a school for some mid-level personnel like foremen, merchant mariners (officers, for the ordinary sailors PTU sufficed), physician assistants, nurses, accountants etc., and is something in between of a normal high school and a community college. While a PTU does not give a right to its graduate to enter a university, a technicum does, and is thus equivalent to a normal middle school. It also has a longer study term (3 years or 4 for a medical fields), a curriculum less centered on the applied skills and more on academical subjects, and its students are usually much older and/or more motivated, so it has little of the aforementioned disciplinary problems. In the Soviet times these schools were much more widespread, because there a) much more places didn't require a higher education diploma, and b) there was much less draft avoidance, as these schools don't exempt their male students from conscription.
University (vysshaya shkola)To enroll in one (or a more specialized equivalent, which may be called an institute or an academy), you need two things. First, you need full 11 years of middle school; if you dropped out before senior school, you have to study at a technicum before you are admitted to a university. Second, you need to pass an EGE ("Unified State Exam"), which is performed at the end of middle school and is a combined graduation-and-entrance exam: the universities set a passing level at certain subjects at which they agree to accept anyone who presents it. EGE is a specifically Russian institution, though many other post-Soviet countries have their own equivalent. It is also a pretty recent invention, introduced in 2009, before that it didn't exist; graduation/matriculation and entrance exams were different beasts of different stripe. In these blessed times (EGE is a very controversial affair, prone to cheating, fraud and accusations of dumbing down) a strait-A student might also get a so-called "Gold Medal", which exempted them from entrance exams entirely and let such a lucky person to enter any university of their choice. Slightly worse performers got Silver Medals which required them to pass only one entrance exam on their selected specialty. After the EGE was introduced, these don't work anymore, though they are still awarded. Universities in the post-Soviet system use fixed curricula just like schools; you choose a specialty and have to study all disciplines included in its "Educational Standard", which is a state-approved document passed down from the Ministry of Education. University alumni may receive the traditional Soviet degree of "Specialist", largely equivalent to a traditional German "Diplom" degree from which it ultimately descended, or Western degrees like Bachelor or Master; the specialist lies in between them. You need 4 years to become a Bachelor, 5 (or 6 for a medical degree) years to become a Specialist, and 6 years to become a Master. The equivalence and acceptance of the Specialist degree in the West varies — sometimes it is perceived as an equivalent to a Master, but in other cases it might be considered a Bachelor or not accepted at all, it depends mainly on the study field, the study term and the reputation of a university that awarded the degree. Another matter that in many Western countries the professional certificates are issued not by the educational institutions as in Russia, but by the professional associations, which require Russian graduates to retake them anyway.
Rural small-class school (selskaya malokomplektnaya shkola)Cities are only a part of Russia. Granted, most of the population is urban, but the country also includes vast stretches of sparsely-populated wilderness with villages. On this territory, the single-room, single-schoolmarm school never fell out of fashion. The quality of education in these schools greatly depends on the schoolmarm in question's personality. An enthusiast can often give education no worse (and sometimes better) than city schools; a slacker gives barely if any.