Mountain Pass Difficulty Ratings

OsmAnd and some other maps label passes with their elevation and a rating (in parentheses, in Russian Cyrillic). This is a Soviet/Russian alpine grade rating of difficulty. If you are familiar with other rating systems from Western Europe and the United States, you can see conversion charts here and here. There is a quick wikipedia explanation of Russian grades here.

As a trekker, you can easily go through passes marked with the Cyrillic Russian letters (Н/К) which stands for "Not Classified," meaning that it's a normal hiking trail (after the snow melts). An example here would be Alauddin Pass in the Fann Mountains. A pass with a grade grade of 1A and 1B (1/Б) are possible in some circumstances, but a 2A and above is for climbers only, meaning that you need ropes, harnesses, crampons, ice axes, gear and climbing experience.

This is how the 1A and 1B are described (in a very brief way):

Grade 1A – Any type of ascent which can be regarded as more than simple hiking. No lower limit of ascent in meters and no specified elevation is needed to qualify for this grade.

Grade 1B – Easy ascent of a peak between 2000–5000 m over rocks, with sections of snow and ice or mixed ground.

As for the 1A and 1B, your ability as a trekker to do them depends on some variables, and the problem with the rating system is that it assumes you have climbing equipment and a team. What I mean is that this grading system is not meant for trekkers. For example, a pass at a not-particularly-high altitude that is accessed on a gently sloping glacier is assessed as a 1B, and is considered very easy for climbers. BUT... this assumes you are in a harness and roped up, because the glacier may have crevasses. So this is what I mean by arguing that it's a difficulty rating more so than a danger rating. A 1B pass may kill a trekker.

But… there are 1A and 1B passes that get that rating based on elevation and steepness of the rocky trail. An example is the very popular Ala-Kol Pass in Kyrgyzstan, which is a 1A. There is no glacier with crevasses to fall into, it's just a 3900 meter pass with a very steep backside descent. If it's mid-summer and you are in good shape and you aren't scared of steep trails with loose rocks, then it's not a problem. An example of a 1B that is trekkable is Chimtarga Pass in Tajikistan, at over 4700 meters. Once the snow melts by early August you can hike through the pass (without putting your hands on the ground or on the rocks). It's a hike, not a scramble or a climb. But, when there is still snow there is the chance that you could slip on a steep slope and slide down a snow field at high speed until you smash into the rocks at the bottom.

The simplest assessment I can give is that a 1A/B pass with a long glacier crossing is not a good idea, and a 1A/B pass that has no glacier is doable after the snow melts. What you need to do is to see an assessment of each pass. For example, Ti Shakh Pass in the Upper Zarafshon mountains goes up a glacier for several kilometers, and shepherds and their flocks do it at the beginning of the summer. But they know the track exactly. And they know where the crevasses - open or hidden - are located. But late in the summer it seems impossible as the crevasses open up. So, early summer is a leisurely stroll behind a flock of sheep, and late summer is a guaranteed death.