Bir yandan bu plan mantıklı, bir yandan da biraz zor görünüyor.

It means something like on the one hand ... on the other hand.

In this sentence, it introduces two different ways of looking at the same plan:

• Bir yandan bu plan mantıklı = on one hand, this plan is logical
• bir yandan da biraz zor görünüyor = on the other hand, it looks a bit difficult

It does not literally mean a physical side here. It is an idiomatic expression for presenting two contrasting or competing impressions.

Because Turkish often uses this as a paired structure:

• bir yandan ...
• bir yandan da ...

This is similar to English paired expressions like:

• on the one hand ... on the other hand
• in one way ... in another way

The repetition helps show that the speaker is balancing two sides of the issue.

Here da adds a sense like also, as well, or and.

So bir yandan da can feel like:

• and on the other hand
• also from another perspective

It helps connect the second clause to the first.

Also, this da is the separate word meaning too / also, not the ending that means in / at. That is why it is written separately.

Because in Turkish, the verb to be is often not expressed in simple present-tense sentences, especially in the third person.

So:

• bu plan mantıklı literally looks like this plan logical
• but it means this plan is logical

This is very normal in Turkish. The same happens with many adjective and noun sentences:

• Hava güzel = the weather is nice
• O yorgun = he/she is tired

Good question. In Turkish, adjectives do usually come before nouns when they directly describe them:

• mantıklı plan = a logical plan

But in bu plan mantıklı, mantıklı is not just modifying the noun inside a noun phrase. It is the predicate of the sentence:

• bu plan = this plan
• mantıklı = logical

So the structure is:

• This plan is logical

That is why mantıklı comes after bu plan.

Mantıklı means logical, reasonable, or sensible.

It comes from mantık = logic, plus the suffix -lı, which often means having / with.

So very literally, mantıklı is something like with logic.

Depending on context, bu plan mantıklı could be understood as:

• this plan is logical
• this plan makes sense
• this plan is reasonable

Biraz means a little, a bit, or somewhat.

Zor means difficult, hard, or sometimes challenging.

So biraz zor means:

• a little difficult
• somewhat hard
• kind of challenging

The word biraz softens the statement. Without it, zor would sound stronger:

• zor görünüyor = it looks difficult
• biraz zor görünüyor = it looks a bit difficult

In this kind of sentence, görünüyor usually means seems, appears, or looks.

So biraz zor görünüyor means:

• it seems a bit difficult
• it looks a bit hard

Even though görünmek is related to seeing/being visible, it is very commonly used in Turkish the way English uses look or seem.

So here it is not about literal eyesight only. It is about impression.

Görünüyor comes from the verb görünmek = to appear, to seem, to be visible.

A simple breakdown is:

• görün- = appear / seem
• -üyor = present continuous / current ongoing form

So görünüyor means:

• it appears
• it seems
• it is looking

In natural English, seems or looks is usually the best translation here.

The subject is still bu plan.

Turkish often leaves out repeated elements when they are already clear from context. So the full idea is:

• Bir yandan bu plan mantıklı, bir yandan da bu plan biraz zor görünüyor.

But repeating bu plan would sound unnecessary. Since both clauses are about the same plan, Turkish simply omits it in the second clause.

English does this too sometimes:

• This plan is logical, but also seems a bit difficult.

Because Turkish strongly tends toward verb-final word order.

So in the second clause:

• bir yandan da biraz zor görünüyor
• literally: on the other hand also a bit difficult seems

That final placement of görünüyor is very typical Turkish sentence structure.

The first clause has no visible verb because it is a nominal sentence with an implied is.

It is usually a mild, balanced contrast.

The speaker is not saying:

• this plan is good but actually bad

Instead, they are saying something more like:

• it has a positive side
• and it also has a difficult side

So the tone is thoughtful and balanced, not dramatic.

Yes, that is a very natural translation.

Other natural English versions include:

• On the one hand, this plan is reasonable; on the other hand, it seems a bit difficult.
• This plan seems sensible, but it also looks a little hard.
• In one way, this plan is logical, but in another way, it seems somewhat difficult.

So the sentence combines approval with hesitation.