First of all,I don't know to whom I reply & give my answer!?? Nice would have been to give us (together with your posted topic) a name (even a pseudo/avatar one!)...
Back to your question,I want to tell you that I completely identified your coins ; you found the correct denominations of only 2 of them (the 1/2 sen & 10 Yen ; the coin you said it is a 1Yen is not! It is a 1 sen coin).
All 3 coins are common coins,of low collectable values. Even if for an ''untrained'' eye as yours (sorry!; I apologize but it is true) the coins look ''in really good condition'',for us (collectors) they are circulated coins,of a medium conservation grade (F to,at most,VF).
Your coins are:
1/2 sen 1887 (emperor Mutsuhito,Meiji era,year 20) ; value:3 $
1 sen 1918 (emperor Yoshihito,Taisho era,year 9) ; value:0.25 usd.
10 Yen 1959-1978.... (emperor Hirohito,Showa era). value:0.10 usd.
Thank You Andi
For the information but i only wanted to know the coins date and value.. to try and date the Merchants TANSU cabinet that i found them hidden in, in a secret compartment.. It is currently being valued by Sotheby's of London so to value of the coins is insignificant to what the cabinet could be worth.