Consider the following system of equations, using standard notations :
Y1 = α0 + α1Y2 + α3Y3 + α4Y4 + α5Y5 + u1
Y2 = β0 + β1Y3 + β2Y1 + β3X2 + u2
Y3 = γ0 + γ1X1 + γ2X2 + γ3X3 + u3
According to order condition, the second equation is
1
Unidentified
2
Just identified
3
Over-identified
4
Not possible to infer identification due to incomplete information.