I've been reading a few post about naruto being stronger than Chunin level, etc. I think is time to clarify "again", that this is naruto and not dragon ball where Saiyan-jin phase 3 is stronger than Saiyan-jin phase 2. Genin, Chunin and Junin are ranks not level of strenght.
Genin (下忍, Genin? literally "Low Ninja", Viz "Junior Ninja") are the lowest level of ninja and also the ones that display the most difference in power. When they become Genin, ninja start to do their bit for their village's economy – being sent on missions that the village gets paid for. They are typically sent either on D-rank missions, which are the lowest rank and are almost entirely risk-free jobs of manual labor, or, very rarely, on C-rank missions, which are a cut above that and begin to verge on real "ninja" work – though they generally have a very low possibility of risk to the ninja involved, especially since their Jonin level sensei often accompanies them. Recently, Konohagakure has been shorthanded in upper-level ninja ever since the attack by Otogakure and Sunagakure, and has been forced to occasionally send Genin on higher-ranked missions, often without the supervision of a Jonin.
Chunin (中忍, Chūnin?, literally "Middle Ninja", Viz "Chūnin" and "Journeyman Ninja") are ninja who are qualified to watch over and guide other ninja. Chunin have reached a level of maturity that primarily consists of leadership skills and tactical prowess. Some of them, like Iruka Umino, function as teachers and others, like Shikamaru Nara, serve as team leaders in charge of small teams who need to make decisions and utilize the skills of the shinobi under their command to the maximum effect. Chunin are typically sent on C or B-rank missions.
To become a Chunin, a Genin participates in a large examination with his or her team, known as the "Chunin Exams". The only shown exam is a three-stage exam: the first stage tests their information gathering abilities and decision-making abilities (as well as their overall understanding of the ninja philosophy), the second stage tests their abilities at accomplishing a mission and adhering to guidelines, and the third consists of fights between those who passed the previous two stages, watched by a council that decides who becomes a Chunin and who does not. While the winners are able to proceed to fight the next opponent, aptitude, rather than winning, is evaluated to determine whether a candidate is promoted; for example, Shikamaru forfeits his first match but is still promoted because of his strategic aptitude in deciding to forfeit because he knew that his Chakra was too low to continue. This way, anybody who makes it to the third stage of the Exams has a chance to become Chunin. However, it is also possible for none of the candidates to become Chunin if the judges believe that they do not have appropriate qualifications.
Jonin (上忍, Jōnin?, literally "High Ninja", Viz "Elite Ninja") are generally highly-experienced ninja with great individual skill who serve as military captains. They are often sent on A-rank missions, and experienced Jonin may even be sent on S-rank missions (which are considered to be the most difficult). They may also carry out these missions alone. They are sometimes assigned as sensei for three-person teams of Genin. It is as of yet unknown what one has to undergo to become one, although it is mentioned in the Naruto Anime Profiles databook that Jonin are appointed, however there was also a mention of a Jonin exam in the Kurama filler arc. Most Jonin are able to use at least two types of elemental jutsu.
Tokubetsu Jonin (特別上忍, Tokubetsu Jōnin?, literally "Special High Ninja" English "Special Jonin", sometimes known as Tokujō for short) are ninja who, rather than all-around Jonin training, have Jonin-level ability in a single area or skill, much like warrant officers of real-world militaries. They are elite specialists in their areas and are often assigned as subordinates to regular Jonin when their services are needed.
One example of a Tokubetsu Jonin would be Ibiki Morino. This character's unique ability to completely understand the workings of the human mind makes him a Jonin-level interrogation expert. Ebisu is another Tokubetsu Jonin that specializes as an elite teacher of young pre-Genin ninja before becoming Konohamaru's sensei in Part II.
Those who have achieved the title of Kage (影, Kage? literally "Shadow") are the leaders of the five most powerful Hidden Villages and generally the most powerful ninja in their respective villages. There may be exceptions, however; for example, a ninja may be the most powerful at the time of being installed as Kage, but may become less powerful upon aging, eventually being surpassed by a more youthful ninja.
Their elite status is also attributed to the tendency for most Kage to have family members who were previous Kage, or be personally taught by a former Kage or student of a former Kage. Examples of this occurrence include Gaara, who succeeded his father as Kazekage; the Fourth Hokage, who was taught by the Third Hokage's student Jiraiya; Tsunade, granddaughter of the First Hokage, grandniece of the Second Hokage, and former student of the Third Hokage; and the Third Hokage who was taught by both the First Hokage and Second Hokage.
Hopes this clarifies everything for those talking about saiyan-jin level one or of chunin being a mere level of strenght.