@User you must give the full path of the node, so if the ring oscillator node is called

inv_1_1/a

and it is placed in a subcircuit instantiated as 'Xringosc' in your testbench you need to set

.ic v(Xringosc.inv_1_1/a)=0

. Otherwise you can try to move the .ic line inside the ringosc subckt.

Okay lemme try that

try the simple solution to move the .ic inside the ringosc subcircuit.

@User The .ic statement works apparently. Thanks. I will also try the other one out