Closet gate for Osaka Castle

I am confused at so many gates. I am a senior traveling form Namba Station.

Osaka Subway - Nagahoribashi to Morinomiya
or
Japan Railways (JR) - Shinimamiya to Morinomiya

Judging rom another thread I thing you will be staying in Namba Oriental Hotel.

Google maps tells you how to get Osaka Castle.

https://bit.ly/2smGTEm

You can take several routes, but I think you might better get off at Tanimachiyonchome metro station. The distance from other stations might be slightly closer than Tanimachiyonchome, but you can save some time for metro ride. The closest gate of Osaka castle to Tanimachiyonchome is Otemon, which is the main gate of Osaka castle, from where you can walk the best route to Osaka Castle.

If you get off Tanimachi line, use exit No. 1A, 1B or 2. If you take Chuo line, use exit No. 9. In any case, just ask the station staff "Osaka castle?". They will show you the right exit.

Where is your starting point (before getting to Namba Station)?

Which station looks most convenient,
subway Namba Station,
JR-Namba Station
or Namba Station of Nankai?

Subway Tanimachi 4-chome [yon-chome] Station
is close to Ote Gate [Otemon] for the castle,
and your walking route seems relatively flat.

- Osaka Subway Route Map
http://www.osakametro.co.jp/library/english/img/map.pdf

　　　Namba (M20)
　　　: Track 2
　http://www.osakametro.co.jp/library/station-guide/M/m20/pdf/station.pd...
　| Midosuji Line
　　　: Track 2
(M18) Hommachi (C16)
　　　: Track 1
　http://www.osakametro.co.jp/library/station-guide/C/c16/pdf/station.pd...
　| Chuo Line
　　　: Track 1
(C18) Tanimachi 4-chome [yon-chome]
　http://www.osakametro.co.jp/library/station-guide/C/c18/pdf/station.pd...
　　　: East Gate
　| Short walking
Osaka Castle: Ote Gate [Otemon].

- Map of Osaka Castle Park
https://osakacastlepark.jp/foreinger/images/English.pdf

Thank you so much. I love this site. The answers I get are incredible. I thank you all for your time.