user3237: I would like to know what are all the most frequent transpositions between the two following openings:
.
The Caro-Kann Panov–Botvinnik Attack with 5...e6 6. Nf3 Bb4:
  [StartPly "12"]

  [FEN ""]
  1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Bb4

.
The Nimzo-Indian Defence:
  [StartPly "6"]

  [FEN ""]
  1. d4 Nf6 2. c4 e6 3. Nc3 Bb4

.
Please try if possible to provide the list of all the transpositions sorted from the most common to the rarest.
.
Edit: I found two transpositions which seem to be very common ones.
Both of these two lines:


d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O cxd4 8. exd4 dxc4 9. Bxc4


d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O dxc4 8. Bxc4 cxd4 9. exd4 


Transpose into this line:


e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Bb4 7. Bd3 dxc4 8. Bxc4 O-O 9. O-O


But there are maybe more transpositions.

user4588: There are indeed a couple of transpositions from the Nimzo-Indian to the Panov variation of the Caro-Kann and they occur sometimes in practical games.
Using a database of chess games, they can be filtered by searching simultaneously on:

The position after 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4
"B10-B19", i.e. the ECO-code of the Caro-Kann.

After finding the games where an actual transposition occured, they can be put in a tree-like structure to count the transpositions.
Using ChessBase Mega Database 2015, 91 games are found, for which both players have a FIDE rating of 2200 or more. Then, the found games were put in a ChessBase tree-file (.ctg).
The most common transpositions found this way are: 

4.e3 0-0 5.Bd3 c5 6.Nf3 d5 7.0-0 cxd4 8.exd4
4.e3 0-0 5.Bd3 d5 6.Nf3 c5 (see 1)
4.e3 c5 5.Nf3 0-0 6.Bd3 (see 1)
4.e3 c5 5.Bd3 0-0 (see 1)


3237: <p>I would like to know what are all the most frequent transpositions between the two following openings:</p>

<p>.</p>

<p>The Caro-Kann Panov–Botvinnik Attack with 5...e6 6. Nf3 Bb4:</p>

<pre><code>  [StartPly "12"]

  [FEN ""]
  1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Bb4
</code></pre>

<p>.</p>

<p>The Nimzo-Indian Defence:</p>

<pre><code>  [StartPly "6"]

  [FEN ""]
  1. d4 Nf6 2. c4 e6 3. Nc3 Bb4
</code></pre>

<p>.</p>

<p>Please try if possible to provide the list of all the transpositions sorted from the most common to the rarest.</p>

<p>.</p>

<p>Edit: I found two transpositions which seem to be very common ones.</p>

<p>Both of these two lines:</p>

<ul>
<li><ol>
<li>d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O cxd4 8. exd4 dxc4 9. Bxc4</li>
</ol></li>
<li><ol>
<li>d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O dxc4 8. Bxc4 cxd4 9. exd4 </li>
</ol></li>
</ul>

<p>Transpose into this line:</p>

<ul>
<li><ol>
<li>e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Bb4 7. Bd3 dxc4 8. Bxc4 O-O 9. O-O</li>
</ol></li>
</ul>

<p>But there are maybe more transpositions.</p>
 4588: <p>There are indeed a couple of transpositions from the Nimzo-Indian to the Panov variation of the Caro-Kann and they occur sometimes in practical games.</p>

<p>Using a database of chess games, they can be filtered by searching simultaneously on:</p>

<ol>
<li>The position after 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4</li>
<li>"B10-B19", i.e. the ECO-code of the Caro-Kann.</li>
</ol>

<p>After finding the games where an actual transposition occured, they can be put in a tree-like structure to count the transpositions.</p>

<p>Using ChessBase Mega Database 2015, 91 games are found, for which both players have a FIDE rating of 2200 or more. Then, the found games were put in a ChessBase tree-file (.ctg).</p>

<p>The most common transpositions found this way are: </p>

<ol>
<li>4.e3 0-0 5.Bd3 c5 6.Nf3 d5 7.0-0 cxd4 8.exd4</li>
<li>4.e3 0-0 5.Bd3 d5 6.Nf3 c5 (see 1)</li>
<li>4.e3 c5 5.Nf3 0-0 6.Bd3 (see 1)</li>
<li>4.e3 c5 5.Bd3 0-0 (see 1)</li>
</ol>
