thin value bet too risky

Blinds 100/200 10 handed
utg1 raises 600 AQ (stack 19k )
md1 re raises 1800 AK (stack 21k )
utg 1 calls 1200 everyone else folds
flop A 6 3 (pot 3900)
utg1 checks , md1 bets 1500 , utg1 raises to 4500 , md1 calls 3000
turn A 6 3 3 (pot 12900)
utg1 checks , md1 bets 3500 , utg1 calls 3500
river A 4 3 3 6 (pot 19900) , utg1 checks ,
we put utg1 on precisely AQ maybe AJs
should md1 make a thin value bet here or is it too risky ? utg1 has 9200 left in his stack , so if md1 bets say another 3500 for value , then utg1 could push and leave md1 with a decision to risk the rest of his chips and preety much his tornament .
reads , utg has played a solid game so far raising in early position with solid values

Definitely value bet. I would be willing to go all in here given the texture of the board. You are ahead of pretty much every likely hand here. If he had 66 he likely would have raised on the turn. He's unlikely to have chased you down with 44 for that river 2 outter. Unlikely he would have A3 or A4 if he's truly solid as you say.

The only other thing is flush but since you didn't mention the suits I assume it was not possible or likely.

thanks for your thoughts
I think your absolutely right , unfortunetly in this tornament I let the villan of cheaply. Especialy because I put the guy on AQ , probably need to trust my reads more often.
no flush possibility

Are you md1? Why are you betting so small? 1000% standard river shove.

not shore why i didnt bet the river , like I said I actually put the player on AQ but didnt trust my read 100% I guess , at the time I was thinking there is already a big pot there and played it abit too safe, after the hand I too thought a value bet was in order. Maybe he wouldnt call a shove but could of easly got another 3500 or so .

The river is a clear value bet. The hands that beat him are pretty unlikely, especially after his opponent checks the river.

What would villain 'check' on the river that would be ahead of you here? (after check/call turn). Nothing.

good point , if he had a set hed be going value for shore , he might check two pair , but thats unlikely as he is a solid player and wouldnt play ace rag in that situation , that leaves AQ , AJ or possibly a pocketr pair , evertything be beat

Thread title is bad, btw. Thin value would be like A8.