I'm amazed at the tenderness : ) by wich some people have created neat spreadsheet here, thank you !
Let's assume the current situation
You have one core deck let's say the 2k/6k deck with other bunches of decks from here and there and you would like to :
=>import the deck by adding tags to the core deck for exemple having a body word list in some way importing it + having body part as tag on your core deck.
=>=> Thus you have the imported words with the sentences from 2k/6k deck.
Of course I hope this is doable without loss of anki data .
Any help or suggestion is welcome thanks.

Up since no reply ... It seems that I need to manipulate the anki files with SQLite queries ?Or maybe is there another simpler way ?

I'm sorry but I don't understand what you are trying to do. So I'll try to clarify..

1. You have a Core deck.

2. You want to merge another deck into this Core deck.

3. You want to automatically add tags to all the words that were imported

Is this correct?

I can suggest one possibility, but hopefully others will chime in if my memory of Anki is wrong or there's an easier or more sophisticated solution.

Just to confirm what you want to do:
Deck A is your main deck (Core6k) which includes some words related to the body.
Deck B is words relating to the body which have at least the tag "body part".
You want to import Deck B such that any duplicate words in Deck A will be tagged "body part" [as well as the remaining newly imported Deck B words.]

I'm assuming you mean vocab words in the Expression field rather than words contained in the examples sentences.

1. Make sure you have/create the appropriate fields in Deck A if you want to update selected fields with data from the other decks. (You might also need to create a temp field in both decks, see 2.)

2. First, "update" Deck A with Deck B. This will update only the duplicates. You select and match which fields you want updated. I believe there's an option to update tags as well. But note:

-Make sure Deck B has exactly the tag(s) you want if you are updating the tags.
-I suspect this will replace the current Deck A tag field (rather than append the new tag(s).) If you want to avoid that, perhaps create a matching temporary field and put [something] in it. After updating you can search for items with [something] in that field in the browser, select all, and add the tag "body part".

3. Next, "import" Deck B into Deck A. Select the setting to ignore duplicates and import only the remaining cards. I believe you can choose to import tags as well, if you want. If Deck B has multiple tags and you want only the "body part" tag, you could instead search in the browser after importing for recently added items, select those, and add the tag.

By the way, Anki also has a forum where you can get assistance with Anki technical questions.
[edits to hopefully make it less confusing]

I don't understand this question at all. I have no idea what OP is trying to do.

hh I think that "updating a deck" resume my problem, I didn't care about the Update button on import tough.

It seems that thora has understand my problem, I tried the steps you provided me and it worked very well thanks.To recapitulate the problem I had in clearer word:
I had a core deck wichi is 2k/6k deck.
I have concurrently other decks such as Minna no nihongo vocabulary etc.

All I wanted to do was to append Tags from Minna no nihongo decks to the core so that It kept tha MNN Tags while showing the core deck exemple sentences wich will stand as my main deck.

Well it worked nice but when it comes to mapping the main field together ... if the fields have a slight difference for exemple : one is in the plain form and the other one is in -masu form there will be no matching.Adding to that that review information are lost.When you import from an anki file you don't have the same options.?

nihongonotame Wrote:hh I think that "updating a deck" resume my problem, I didn't care about the Update button on import tough.

Did you mean "resolved (fixed) my problem"? I hope so. ("resume" means to continue, start again). I'm not quite sure what you mean about the update button. You hadn't noticed it?

Quote:Well it worked nice but when it comes to mapping the main field together ... if the fields have a slight difference for exemple : one is in the plain form and the other one is in -masu form there will be no matching.

This is unavoidable.

Quote:Adding to that that review information are lost.When you import from an anki file you don't have the same options.?

If you update a current Deck A card, the review information of that card will stay as it was in Deck A. You are only updating content fields.

If you import an Anki Deck B into Deck A, I believe the cards will keep their original Deck B review information (as well as fields, layout, etc.)

I wasn't very clear. The update function is only available when importing a text csv file, not when importing an anki deck. (I think the tag field is the last field. It seems like you figured that out, though.) I guess the option to select fields/tags to import isn't available when importing a deck. My mistake. I've only used text files.

If the Deck B review stats are most important to you, consider:

* Updating Deck B with Deck A to get the Core sentences and any other fields you want.
(You'd have to add those new fields to Deck B first.)
* Importing Deck B into Deck A (include duplicates) with the tag you want
* In the browser, search for duplicates in the vocab word field and delete the ones without the new tag (the Deck A ones). (Assuming your Core deck didn't already have duplicate vocab words.)

Are there enough dups to make it worthwhile?
If there's a better way, can someone let the OP know or direct him to a useful Anki help file?